Moving Picture Coding Method, Moving Picture Coding Apparatus, Moving Picture Decoding Method, Moving Picture Decoding Apparatus, and Moving Picture Coding and Decoding Apparatus

ABSTRACT

A moving picture coding apparatus includes an intra-inter prediction unit which calculates a second motion vector by performing a scaling process on a first motion vector of a temporally neighboring corresponding block, when selectively adding, to a list, a motion vector of each of one or more corresponding blocks each of which is either a block included in a current picture to be coded and spatially neighboring a current block to be coded or a block included in a picture other than the current picture and temporally neighboring the current block, determines whether the second motion vector has a magnitude that is within a predetermined magnitude or not within the predetermined magnitude, and adds the second motion vector to the list when the intra-inter prediction unit determines that the second motion vector has a magnitude that is within the predetermined magnitude range.

RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.15/345,920 filed Nov. 8, 2016, which is a Continuation of U.S.application Ser. No. 14/729,321 filed Jun. 3, 2015, now abandoned, whichis a Continuation of U.S. application Ser. No. 14/490,910 filed Sep. 19,2014, now U.S. Pat. No. 9,094,682, which is a Continuation of U.S.application Ser. No. 14/058,636 filed Oct. 21, 2013, now U.S. Pat. No.8,885,722, which is a Divisional of U.S. application Ser. No. 13/712,041filed Dec. 12, 2012, now U.S. Pat. No. 8,867,620, which claims thebenefit of U.S. Provisional Application No. 61/576,501 filed Dec. 16,2011.

FIELD

The present disclosure relates to a moving picture coding method forcoding pictures on a block-by-block basis, and a moving picture decodingmethod for decoding pictures on a block-by-block basis.

BACKGROUND

In inter prediction decoding in H.264, picture data of a current blockis decoded by predicting a bi-predictive reference block included in a Bslice using, as references, two items of picture data which is data ofpictures different from the picture including the current block.

For the H.264 standard, there are motion vector derivation modesavailable for picture prediction. The modes are referred to as directmodes (see 8.4.1.2.1, 3.45, etc. of NPL 1).

The following two modes of (S) and (T) are available as the direct modesin H.264.

(T): Temporal direct mode (temporal mode). A current block is predictedusing a motion vector mvCol of a co-located block (Col_Blk), which isspatially identical to the current block (but temporally different), isscaled by a certain percentage.

(S): Spatial direct mode. A current block is predicted using data on amotion vector (motion data) of a block which is spatially different (butis to be displayed at the same time as a current block).

CITATION LIST Non-Patent Literature

[NPL 1] ITU-T H.264 03/2010

[NPL 2] WD4: Working Draft 4 of High-Efficiency Video Coding JointCollaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 andISO/IEC JTC1/SC29/WG11 6th Meeting: Torino, IT, 14-22 July, 2011,Document: JCTVC-F803_d2

SUMMARY Technical Problem

However, prediction in the temporal direct mode involves multiplicationfor scaling. Such multiplication may cause increase in load in coding ordecoding because motion vectors used in coding or decoding may need tobe handled at a higher bit precision.

In view of this, one non-limiting and exemplary embodiment provides amoving picture coding method and a moving picture decoding method eachof which may cause reduced load and be performed with the same codingefficiency.

Solution to Problem

A moving picture coding method according to an aspect of the presentdisclosure is a moving picture coding method for coding pictures on ablock-by-block basis, and includes: selectively adding, to a list, amotion vector of each of one or more corresponding blocks each of whichis (i) a block included in a current picture to be coded and spatiallyneighboring a current block to be coded or (ii) a block included in apicture other than the current picture and temporally neighboring thecurrent block; selecting a motion vector from among the motion vectorsin the list, the selected motion vector being to be used for coding thecurrent block; and coding the current block using the motion vectorselected in the selecting, wherein in the adding, a scaling process isperformed on a first motion vector of the temporally neighboringcorresponding block to calculate a second motion vector, whether thecalculated second motion vector has a magnitude that is within apredetermined magnitude range or a magnitude that is not within thepredetermined magnitude is determined, and the second motion vector isadded to the list as the motion vector of the corresponding block whenit is determined that the second motion vector has a magnitude that iswithin the predetermined magnitude range.

Furthermore, a moving picture decoding method according to an aspect ofthe present disclosure is a moving picture decoding method for decodingpictures on a block-by-block basis, and includes: selectively adding, toa list, a motion vector of each of one or more corresponding blocks eachof which is (i) a block included in a current picture to be decoded andspatially neighboring a current block to be decoded or (ii) a blockincluded in a picture other than the current picture and temporallyneighboring the current block; selecting a motion vector from among themotion vectors in the list, the selected motion vector being to be usedfor decoding the current block; and decoding the current block using themotion vector selected in the selecting, wherein in the adding, ascaling process is performed on a first motion vector of the temporallyneighboring corresponding block to calculate a second motion vector,whether the calculated second motion vector has a magnitude that iswithin a predetermined magnitude range or a magnitude that is not withinthe predetermined magnitude is determined, and the second motion vectoris added to the list as the motion vector of the corresponding blockwhen it is determined that the second motion vector has a magnitude thatis within the predetermined magnitude range.

These general and specific aspects may be implemented using a system, amethod, an integrated circuit, a computer program, or acomputer-readable recording medium such as a CD-ROM, or any combinationof systems, methods, integrated circuits, computer programs, orcomputer-readable recording media.

Additional benefits and advantages of the disclosed embodiments will beapparent from the Specification and Drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the Specification and Drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

ADVANTAGEOUS EFFECTS

The moving picture coding methods and the moving picture decodingmethods disclosed herein each enables coding or decoding of movingpictures with reduced processing load while causing no reduction incoding efficiency.

BRIEF DESCRIPTION OF DRAWINGS

These and other objects, advantages and features of the disclosure willbecome apparent from the following description thereof taken inconjunction with the accompanying drawings that illustrate a specificembodiment of the present disclosure.

FIG. 1 illustrates two pictures referenced for decoding of a currentblock (Curr_Blk).

FIG. 2A illustrates a reference picture list (RefPicList0).

FIG. 2B illustrates a reference picture list (RefPicList1).

FIG. 3 illustrates picNum in the reference picture lists RefPicList0 andRefPicList1 of the CurrBlk included.

FIG. 4 illustrates information for use in a (T) temporal mode.

FIG. 5A illustrates a scaling process in the temporal mode, showing asimplified diagram of a co-located block and a motion vector mvL0Col.

FIG. 5B illustrates a scaling process in the temporal mode using adiagram of concept of the scaling process.

FIG. 6 illustrates a relationship between STEPs 1 to 3 and equations forderiving motion vectors described in NPL 1.

FIG. 7 illustrates a (S) spatial direct mode.

FIG. 8 is a block diagram illustrating a configuration of a movingpicture coding apparatus according to Embodiment 1.

FIG. 9 is a flowchart illustrating operation of the moving picturecoding apparatus according to Embodiment 1.

FIG. 10 illustrates merging candidate blocks [1 . . . 6] set by anintra-inter prediction unit.

FIG. 11 illustrates concept of the merging candidate list(mergeCandList).

FIG. 12 illustrates an example case where the inter-intra predictionunit determines that motion data is a duplicate.

FIG. 13 is a flowchart illustrating a process for obtaining motion dataof a merging candidate block [i].

FIG. 14 is a flow chart illustrating an example of a scaling processperformed by the inter-intra prediction unit.

FIG. 15 is a flow chart illustrating another example of the scalingprocess performed by the inter-intra prediction unit.

FIG. 16 is a block diagram illustrating a configuration of a movingpicture decoding apparatus according to Embodiment 1.

FIG. 17 is a flowchart illustrating operation of the moving picturedecoding apparatus according to Embodiment 1.

FIG. 18 illustrates update of a merging candidate list (mergeCandList)using (a) a generated initial merging candidate list (mergeCandList) and(b) a merging candidate list after being updated.

FIG. 19A illustrates a motion vector predictor mvpLX in HEVC.

FIG. 19B illustrates a candidate list mvpListLX (mvpListL0 andmvpListL1) for the motion vector predictor mvpLX.

FIG. 20 illustrates predictor candidate blocks or a predictor candidateblock.

FIG. 21 shows an overall configuration of a content providing system forimplementing content distribution services.

FIG. 22 shows an overall configuration of a digital broadcasting system.

FIG. 23 shows a block diagram illustrating an example of a configurationof a television.

FIG. 24 shows a block diagram illustrating an example of a configurationof an information reproducing/recording unit that reads and writesinformation from and on a recording medium that is an optical disk.

FIG. 25 shows an example of a configuration of a recording medium thatis an optical disk.

FIG. 26A shows an example of a cellular phone.

FIG. 26B is a block diagram showing an example of a configuration of acellular phone.

FIG. 27 illustrates a structure of multiplexed data.

FIG. 28 schematically shows how each stream is multiplexed inmultiplexed data.

FIG. 29 shows how a video stream is stored in a stream of PES packets inmore detail.

FIG. 30 shows a structure of TS packets and source packets in themultiplexed data.

FIG. 31 shows a data structure of a PMT.

FIG. 32 shows an internal structure of multiplexed data information.

FIG. 33 shows an internal structure of stream attribute information.

FIG. 34 shows steps for identifying video data.

FIG. 35 shows an example of a configuration of an integrated circuit forimplementing the moving picture coding method and the moving picturedecoding method according to each of embodiments.

FIG. 36 shows a configuration for switching between driving frequencies.

FIG. 37 shows steps for identifying video data and switching betweendriving frequencies.

FIG. 38 shows an example of a look-up table in which video datastandards are associated with driving frequencies.

FIG. 39A is a diagram showing an example of a configuration for sharinga module of a signal processing unit.

FIG. 39B is a diagram showing another example of a configuration forsharing a module of the signal processing unit.

DESCRIPTION OF EMBODIMENTS

(Underlying Knowledge Forming Basis of the Present Disclosure)

FIG. 1 illustrates a configuration of a picture coding apparatus inaccordance with the standard of HEVC.

(Underlying Knowledge Forming Basis of the Present Disclosure)

FIG. 1 illustrates two pictures referenced for decoding of a currentblock (Curr_Blk). In FIG. 1, the numbers “300” to “304” are picturenumbers (PicNum), and the pictures are arranged in ascending order ofvalues of display order (PicOrderCnt). The current block to be decodedis included in a picture numbered 302 (CurrPic). In this example, thecurrent block to be decoded references a picture having a PicNum of 301and a picture having a PicNum of 304. The picture having a PicNum of 301precedes the picture including the current block in the display order,and the picture having a PicNum of 304 follows the picture including thecurrent block in the display order. In the following Drawings, thestarting point of an arrow indicates a referencing picture (a picture tobe decoded) and the head of an arrow indicates a picture to be used fordecoding (a picture to be referenced) as described in the legend to FIG.1.

Current blocks to be decoded are indicated by a solid black block in thefollowing Drawings, and simply referred to as Curr_Blk in the Drawingand following description. Again, the starting point of an arrowindicates a referencing picture (a picture to be decoded) and the headof an arrow indicates a picture to be used for decoding (a picture to bereferenced) as described in the legend to FIG. 1. The picture having apicNum of 302 is a picture including a current block to be decoded (acurrent picture to be decoded).

FIG. 2A and FIG. 2B illustrate two reference picture lists, RefPicList0and RefPicList1, respectively.

FIG. 2A illustrates a reference picture list 0 (RefPicList0) which is alist for identifying one of two reference pictures. FIG. 2B shows areference picture list 1 (RefPicList1) which is a list for identifyingthe other of the two reference pictures. By using the reference picturelists, it is possible to specify a reference picture referenced by acurrent picture to be decoded, using an index having a small value suchas “0” or “1” (refIdxL0 and refIdxL1) instead of the picNum having alarge value such as “302”. Pictures referenced by current blocks to bedecoded (Curr_Blk), which are blocks in a slice, are indicated using thevalues in these lists.

These lists are initialized (generated) when a B slice including acurrent block is decoded.

Entries in the reference picture lists RefPicList0 and RefPicList1 arereordered so that indices having less values in the reference picturelist RefPicList0 and the reference picture list RefPicList1 indicatepictures having different picture numbers picNum. Each of the referencepicture lists are divided into the first half including picturespreceding the picNum302 and the second half including pictures followingthe picNum302. In the first half of the reference picture list 0, thepicture indices are assigned picture numbers in descending order (301,300 . . . ). In the first half of the reference picture list 1, thepicture indices are assigned picture numbers in ascending order (303,304 . . . ).

For example, when a code sequence has an index having a minimum value“0” for each of the reference picture list 0 and the reference picturelist 1, the following two reference pictures are determined for thepicture 302.

One of the reference pictures is a picture indicated by RefPicList0[0],which is a picture 301 immediately before the picture 302. The other ofthe reference pictures is a picture indicated by RefPicList1[0], whichis a picture 303 immediately after the picture 302.

In the example illustrated in FIG. 1, one index refIdxL0 is 0, andtherefore the current picture 302 references the picture 301. The otherindex refIdxL1 is 1, and therefore the current picture 302 referencesthe picture 304.

FIG. 3 illustrates picNum in the case where the values of refIdxL0 andrefIdxL1 in each of the reference picture lists RefPicList0 andRefPicList1 of the CurrBlk included in the picture 302 increase from“0”. Greater values in the list (the value of refIdxL0 and the value ofrefIdxL1) indicate pictures more distant from the current picture to bedecoded (picNum302).

Particularly, RefPicList1, which indicates the other reference, holdsindices under a rule that indices having less values in the list areassigned pictures following the CurrPic picture 302 (that is, picturesgreater than PicOrderCnt (CurrPic) and already decoded and stored in thememory) in descending order (the rule is referred to as Rule 1). Underthe Rule 1, the picture indicated by RefPicList1[0] is a picture picNum303 indicated by a dashed circle in FIG. 3.

As seen above, the one reference picture list is simply referred to asRefPicList0 and the indices in the list are simply referred to asrefIdxL0 in the Description and the Drawings unless otherwise noted.Similarly, the other reference picture list is simply referred to asRefPicList1 and the indices in the list are simply referred to asrefIdxL1 (see the legends to FIG. 3 and NPL 1, 8.2.4.2.3 in 8.2.4Decoding process for reference picture lists construction for morederails.)

The following will describe the (T) temporal mode and the (S) spatialdirect mode in H.264.

FIG. 4 illustrates information for use in the (T) temporal mode.

The hatched block in FIG. 4 represents a co-located block (Col_Blk),which is spatially identical to the current block (but temporallydifferent from the current block). Temporal location of the co-locatedblock is specified by the index having a value of “0” in the RefPicList1in the other reference picture list 1 in FIG. 3, that is, the co-locatedblock is located in the picture 303. In the list RefPicList1 initializedunder the Rule 1, the picture indicated by the index having a value of“0” (that is, the value of RefPicList1[0]) is a picture temporallyclosest one of the pictures which are in the reference memory and followthe current picture in the display order with exceptional cases inwhich, for example, the reference memory stores no picture temporallyfollowing the current picture.

Next, in the temporal mode, motion vectors mvL0 and mvL1 of a currentblock to be decoded Curr_Blk represented as a solid black block arederived using “motion data” of the Col_Blk represented as a hatchedblock. The “motion data” includes the following.

(i) Reference picture refIdxL0[refidx] referenced by the Col_Blk

In this example, the Col_Blk references the picture having a picNum of301 (this is indicated by the value of RefPicList0[1]).

(ii) Motion vector mvL0Col in the reference picture

In FIG. 4, the dashed arrow in the picture having a picNum of 301indicates one motion vector mvL0Col to be used for decoding of theCol_Blk.

In the following, dashed arrows in the present Description and theDrawings represent motion vectors. The motion vector mvL0Col indicates apredictive image used for decoding of Col_Blk.

FIG. 5A and FIG. 5B illustrate a scaling process in the temporal mode.

The scaling process is a process for derivation of motion vectors mvL0and mvL1 of a current block to be decoded Curr_Blk by scaling the valueof a motion vector mvL0Col using the ratio between distances from thecurrent block to reference pictures.

FIG. 5A illustrates the reference structure, co-located block, andmotion vector mvL0Col in FIGS. 1 to 4 using a simplified diagram.

FIG. 5B illustrates concept of the scaling process.

The scaling process is based on the idea of similarity between atriangle DEF and a triangle ABC as illustrated in FIG. 5B.

The triangle DEF is a triangle for Col_Blk.

The point D is on the Col_Blk. The point E is on a picture referenced bythe Col_Blk. The point F is a point where the motion vector mvL0Colstarting at the point E has its tip.

The triangle ABC is a triangle for Curr_Blk.

The point A is on a current block to be decoded Curr_Blk. The point B ison a picture referenced by the block Curr_Blk. The point C is a pointwhere the vector to be derived has its tip.

First, in STEP 1, ScaleFactor is derived which is a ratio of (2) arelative distance (tx) from the Col_Blk to a picture referenced by theCol_Blk to (1) a relative distance (tb) from the Curr_Blk to a picturereferenced by the Curr_Blk. For example, referring to FIG. 5B,ScaleFactor is a ratio of tb=302−301=1 to tx=303−301=2 (tb/tx), that is,the scaling ratio is 0.5 (1/2) (or the homothetic ratio is 1:2).Therefore, it is the case that the homothetic ratio of the triangle ABCto the triangle DEF is 1/2.

ScaleFactor=tb/tx=(302−301)/(303−301)=1/2   (STEP 1)

In STEP 2, a vector EF having a magnitude equal to the length of a givenside EF is multiplied by the scaling ratio to obtain a vector BC. Thevector BC is one of two vectors to be derived, a vector mvL0.

mvL0=ScaleFactor.times.mvL0Col   (STEP 2)

In STEP 3, the other vector to be derived, a vector mvL1, is derivedusing the mvL0 derived in STEP 2 and an inverted mvL0Col.

mvL1=mvL0−mvL0Col   (STEP 3)

FIG. 6 illustrates a relationship between STEPs 1 to 3 and the equationsfor deriving motion vectors described in 8.4.1.2.3 Derivation processfor temporal direct luma motion vector and reference index predictionmode of NPL 1.

FIG. 7 illustrates the other one of the two direct modes, the (S)spatial direct mode.

A current block to be decoded (Curr_Blk) is included in a motioncompensation unit block. In this mode, data on a motion vector (this ismotion data including a combination of values (motion vector mvLXN andreference index refIdxLXN) as described above, the same applieshereinafter) is obtained for a block N which neighbors the motioncompensation unit block (the block N is, for example, a neighboringblock A, a neighboring block B, or a neighboring block C).

Among data on a motion vector (hereinafter also referred to as motiondata), an item of motion data (refIdxL0 and refIdxL0 and mvL0 and mvL1corresponding to them, respectively) of a block having the smallestreference index (refIdxLXN) value is used as it is (see equations 8-186and 8-187 in NPL 1). The reference indices have values of naturalnumbers including “0” (values of MinPositive values). Specifically,refIdxL0 and refIdxL1 are derived using the following equations,respectively:

refIdxL0=MinPositive(refIdxL0A,MinPositive(refIdxL0B,refIdxL0C))  (8-186);

and

refIdxL1=MinPositive(refIdxL1A,MinPositive(refIdxL1B,refIdxL1C))  (8-187).

In the spatial direct mode, items of “motion data” including data on amotion vector mvL0 or mvL1, such as a distance from the current pictureto a reference picture (refIdxL0, refIdxL1), is used in a set.Therefore, unlike in the temporal mode, derivation of a motion vectorgenerally does not involve scaling of mvL0 or mvL1 but only referencesto a reference picture used for the neighboring block.

As described above, derivation of a motion vector mvL0 using ScaleFactor(DistScaleFactor) in the (T) temporal mode involves multiplication ofmvL0Col by ScaleFactor. Accordingly, when a motion vector to be handledin decoding is limited to a magnitude such that the motion vector can berepresented at a certain bit precision, it is necessary to controlgeneration of a motion vector so that the motion vector obtained as aresult of multiplication performed in coding in temporal mode has suchmagnitude. Such control will increase processing load in coding.

Furthermore, according to the conventional H.264 standard, switchingbetween the (T) temporal mode and the (S) spatial direct mode is allowedonly up to once per slice.

For the HEVC standard, use of a merge mode is discussed in which motionvectors are derived using a method more flexible than when the spatialdirect mode or the temporal mode is used for each slice in H.264. Here,it is desired to appropriately balance between reduction in processingload and maintenance of coding efficiency for derivation of such motionvectors having a limited magnitude by using these modes in combinationwith the merge mode for a new standard, the HEVC.

A moving picture coding method according to an aspect of the presentdisclosure is a moving picture coding method for coding pictures on ablock-by-block basis, and includes: selectively adding, to a list, amotion vector of each of one or more corresponding blocks each of whichis (i) a block included in a current picture to be coded and spatiallyneighboring a current block to be coded or (ii) a block included in apicture other than the current picture and temporally neighboring thecurrent block; selecting a motion vector from among the motion vectorsin the list, the selected motion vector being to be used for coding thecurrent block; and coding the current block using the motion vectorselected in the selecting, wherein in the adding, a scaling process isperformed on a first motion vector of the temporally neighboringcorresponding block to calculate a second motion vector, whether thecalculated second motion vector has a magnitude that is within apredetermined magnitude range or a magnitude that is not within thepredetermined magnitude is determined, and the second motion vector isadded to the list as the motion vector of the corresponding block whenit is determined that the second motion vector has a magnitude that iswithin the predetermined magnitude range.

In this way, it is possible to limit motion vectors handled in codingand decoding to a certain magnitude such that the motion vectors can berepresented at a certain bit precision.

Furthermore, in the adding, when it is determined that the second motionvector has a magnitude that is not within the predetermined magnituderange, the second motion vector is clipped to have a magnitude withinthe predetermined magnitude range, and a motion vector resulting fromthe clipping of the second motion vector is added to the list as themotion vector of the corresponding block.

Furthermore, in the adding, when it is determined that the second motionvector has a magnitude that is not within the predetermined magnituderange, the second motion vector is not added to the list.

Furthermore, the list is a merging candidate list which lists the motionvector of the corresponding block and specifying information forspecifying a picture referenced by the corresponding block, in theadding, the specifying information is added to the merging candidatelist in addition to the motion vector of the corresponding block, in theselecting, a motion vector and specifying information which are to beused for coding the current block are selected from among the motionvectors in the merging candidate list, and in the coding, the currentblock is coded by generating a predictive picture of the current blockusing the motion vector and specifying information selected in theselecting.

Furthermore, the list is a motion vector predictor candidate list, inthe adding, whether a fourth motion vector has a magnitude that iswithin a predetermined magnitude range or a magnitude that is not withinthe predetermined magnitude range is further determined, and the fourthmotion vector is added to the motion vector predictor candidate list asa motion predictor vector candidate when it is determined that thefourth motion vector has a magnitude that is within the predeterminedmagnitude range, the fourth motion vector being calculated by performinga scaling process on a third motion vector of the spatially neighboringcorresponding block, in the selecting, a motion vector predictor to beused for coding the current block is selected from the motion vectorpredictor candidate list, and in the coding, the coding of the currentblock which includes coding of a motion vector of the current blockusing the motion vector predictor selected in the selecting isperformed.

Furthermore, in the adding, when it is determined that the fourth motionvector has a magnitude that is not within the predetermined magnituderange, the fourth motion vector is clipped to have a magnitude withinthe predetermined magnitude range, and a motion vector resulting fromthe clipping of the fourth motion vector is added to the motion vectorpredictor candidate list as the motion vector predictor candidate.

Furthermore, the predetermined magnitude range is determined based on abit precision of a motion vector, and the bit precision has either avalue specified by one of a profile and a level or by a value includedin a header.

Furthermore, a moving picture decoding method according to an aspect ofthe present disclosure is a moving picture decoding method for decodingpictures on a block-by-block basis, and includes: selectively adding, toa list, a motion vector of each of one or more corresponding blocks eachof which is (i) a block included in a current picture to be decoded andspatially neighboring a current block to be decoded or (ii) a blockincluded in a picture other than the current picture and temporallyneighboring the current block; selecting a motion vector from among themotion vectors in the list, the selected motion vector being to be usedfor decoding the current block; and decoding the current block using themotion vector selected in the selecting, wherein in the adding, ascaling process is performed on a first motion vector of the temporallyneighboring corresponding block to calculate a second motion vector,whether the calculated second motion vector has a magnitude that iswithin a predetermined magnitude range or a magnitude that is not withinthe predetermined magnitude is determined, and the second motion vectoris added to the list as the motion vector of the corresponding blockwhen it is determined that the second motion vector has a magnitude thatis within the predetermined magnitude range.

In this way, it is possible to limit motion vectors handled in codingand decoding to a certain magnitude such that the motion vectors can berepresented at a certain bit precision.

Furthermore, in the adding, when it is determined that the second motionvector has a magnitude that is not within the predetermined magnituderange, the second motion vector is clipped to have a magnitude withinthe predetermined magnitude range, and a motion vector resulting fromthe clipping of the second motion vector is added to the list.

Furthermore, in the adding, when it is determined that the second motionvector has a magnitude that is not within the predetermined magnituderange, the second motion vector is not added to the list.

Furthermore, the list is a merging candidate list which lists the motionvector of the corresponding block and specifying information forspecifying a picture referenced by the corresponding block, in theadding, the specifying information is added to the merging candidatelist in addition to the motion vector of the corresponding block, in theselecting, a motion vector and specifying information which are to beused for decoding the current block are selected from among the motionvectors in the merging candidate list, and in the decoding, the currentblock is decoded by generating a predictive picture of the current blockusing the motion vector and specifying information selected in theselecting.

Furthermore, the list is a motion vector predictor candidate list, inthe adding, whether a fourth motion vector has a magnitude that iswithin a predetermined magnitude range or a magnitude that is not withinthe predetermined magnitude range is further determined, and the fourthmotion vector is added to the motion vector predictor candidate list asa motion predictor vector candidate when it is determined that thefourth motion vector has a magnitude that is within the predeterminedmagnitude range, the fourth motion vector being calculated by performinga scaling process on a third motion vector of the spatially neighboringcorresponding block, in the selecting, a motion vector predictor to beused for decoding the current block is selected from the motion vectorpredictor candidate list, and in the decoding, the decoding of thecurrent block which includes decoding of a motion vector of the currentblock using the motion vector predictor selected in the selecting isperformed.

Furthermore, in the adding, when it is determined that the fourth motionvector has a magnitude that is not within the predetermined magnituderange, the fourth motion vector is clipped to have a magnitude withinthe predetermined magnitude range, and a motion vector resulting fromthe clipping of the fourth motion vector is added to the motion vectorpredictor candidate list as the motion vector predictor candidate.

Furthermore, the predetermined magnitude range is determined based on abit precision of a motion vector, and the bit precision has either avalue specified by one of a profile and a level or by a value includedin a header.

These general and specific aspects may be implemented using a system, amethod, an integrated circuit, a computer program, or acomputer-readable recording medium such as a CD-ROM, or any combinationof systems, methods, integrated circuits, computer programs, orcomputer-readable recording media.

Hereinafter, embodiments of the present disclosure are specificallydescribed with reference to the Drawings.

Each of the embodiments described below shows a general or specificexample. The numerical values, shapes, materials, structural elements,the arrangement and connection of the structural elements, steps, theprocessing order of the steps etc. shown in the following embodimentsare mere examples, and therefore do not limit the scope of the Claims.Therefore, among the structural elements in the following exemplaryembodiments, structural elements not recited in any one of theindependent claims are described as arbitrary structural elements.

Embodiment 1

FIG. 8 is a block diagram illustrating a configuration of a movingpicture coding apparatus according to Embodiment 1.

As illustrated in FIG. 8, a moving picture coding apparatus 100includes, as its main part, a subtractor unit 101, a transformation unit102, a quantization unit 103, an entropy coding unit 110, aninverse-quantization unit 104, an inverse-conversion unit 105, an adderunit 106, a memory unit 109, an intra-inter prediction unit 107, and acoding control unit 108.

The subtractor unit 101 outputs a differential signal which is adifference between an input video signal and a predictive video signal.

The transformation unit 102 transforms the differential signal from animage domain into a frequency domain. The quantization unit 103quantizes the differential signal in a frequency domain as a result ofthe transformation and outputs the quantized differential signal.

The entropy coding unit 110 entropy-codes the quantized differentialsignal and a decode control signal and outputs a coded bitstream.

The inverse-quantization unit 104 inverse-quantizes the quantizeddifferential signal. The inverse-transformation unit 105inverse-transforms the inverse-quantized differential signal from afrequency domain into an image domain and outputs a restoreddifferential signal.

The adder unit 106 adds the restored differential signal and apredictive video signal to generate a decoded video signal.

The intra-inter prediction unit 107 stores the decoded video signal onthe basis of a predetermined unit, such as on a per-frame basis or aper-block basis, in the memory 109 and, upon instruction from the codingcontrol unit 108, generates and outputs a predictive video signal (pixelvalues derived based on the decoded video signal and motion vectors) tobe provided to the subtractor unit 101 and the adder unit 106.

Furthermore, the intra-inter prediction unit 107 derives a mergingcandidate list (mergeCandList) which is a list of candidate motionvectors for use in coding and decoding performed in merge mode. Toderive the merging candidate list, the intra-inter prediction unit 107selectively adds, to the merging candidate list, a motion vector of eachcorresponding block. Each of the corresponding blocks is (i) a blockincluded in a current picture to be coded and spatially neighboring acurrent block to be coded or (ii) a block included in a picture otherthan the current picture and temporally neighboring the current block.Furthermore, the intra-inter prediction unit 107 performs a scalingprocess on a first motion vector of the temporally neighboringcorresponding block to calculate a second motion vector, and determineswhether the second motion vector has a magnitude that is within apredetermined magnitude range or a magnitude that is not within thepredetermined magnitude range. When determining that the second motionvector has a magnitude that is within the predetermined magnitude range,the intra-inter prediction unit 107 adds, to the merging candidate list,the second motion vector as a motion vector of a corresponding block.The intra-inter prediction unit 107 selects a motion vector to be usedfor coding of a current block from the merging candidate list. In otherwords, the scaling process according to Embodiment 1 is performed mainlyby the intra-inter prediction unit 107. It should be noted that theintra-inter prediction unit 107 of the moving picture coding apparatus100 according to Embodiment 1 corresponds to an adding unit and aselecting unit, and the subtractor unit 101, the transformation unit102, the quantization unit 103, and the entropy coding unit 110 of themoving picture coding apparatus 100 according to Embodiment 1 correspondto a coding unit.

The coding control unit 108 determines control parameters forcontrolling the processing units in FIG. 8 and for controlling coding ofa picture on the basis of a result of a trial, and provided theparameters particularly to the intra-inter prediction unit 107. (Thecontrol parameters correspond to a decode control signal). The trial isperformed using, for example, a function for reducing the bit length ofa coded bitstream represented by a dashed line in FIG. 8. The controlparameters for coding a video data (for example, parameters indicatingeither inter prediction or intra prediction) are thereby determined andoutputted. The outputted signal includes motion vector indices, whichwill be described later.

When the result of the trial is affirmative, the coding control unit 108determines a merging index (merge_Idx) which is a value indicating thatthat the scaling process according to Embodiment 1 has been applied tothe picture, and includes the merging index in a decode control signalto be outputted. In this case, the quantized differential signal hasvalues derived from a predictive video signal generated using thescaling process according to Embodiment 1.

FIG. 9 is a flowchart illustrating operation of the moving picturecoding apparatus according to Embodiment 1.

The following will describe operation of coding in merge mode in thecase where the coding control unit 108 has determined to (1) inter-codea current block (MODE_INTER) and (2) use the merge mode (MergeMODE) (orobtain a result of use of the merge mode).

The merge mode in HEVC is conceptually equivalent to a direct mode newlyprovided in the H.264 standard. As with the direct mode in H.264, amotion vector is derived not using a code sequence but using a motionvector of a (S) spatially or (T) temporally different block.

The merge mode and the direct mode in H.264 are different in thefollowing points.

(a) Processing unit: Switching between using and not using the mergemode is possible by switching merge_flag, which can be switched in aprediction unit (PU) less than a slice.

(b) Options: Selection of (S) spatial direct mode or (T) temporal modeis not two-alternative determination. There are more options and theselection is indicated by merge_idx. Specifically, a merging candidatelist (mergeCandList) is derived which is a list of candidate motionvectors for use in coding and decoding in merge mode. A motion vector tobe used is indicated by the value of an index (merge_idx) selected froma code sequence in the list.

When the process for the merge mode is started, the coding control unit108 sets the values of merge_idx and i to “0” (Step S101). The parameteri is conveniently used as a candidate number to distinguish candidates.

The intra-inter prediction unit 107 sets candidate blocks [1 . . . N]each of which is of either of the following two types (Step S102).Assume that N=6.

(s) The candidate blocks [1 . . . (N−1)] are one or more candidateblocks for spatial direct mode. These candidate blocks [1 . . . 5] aredistinguished on the basis of the location of each candidate block.

(t) The candidate block [N] is a candidate block for temporal mode. Aco-located block appended to the candidate blocks for spatial directmode has an entry value of “6”, which is used as the index of theco-located block. This will be described later using FIG. 10.

In Steps S103 and later, the coding control unit 108 performs a loopprocess with increments in the value of the parameter i which indicateseach candidate (Step S103), to determine a mode for derivation of amotion vector to be outputted. The determined motion vector isappropriate for an objective function to provide high accuracy.

The intra-inter prediction unit 107 determines whether or not thecandidate block [i] is available on memory (Step S104). For example, ablock positioned below the current block and yet to be coded (ordecoded) is not stored in memory, and is therefore determined to be notavailable.

When a block is determined to be not available (Step S104, No), theintra-inter prediction unit 107 moves on to the next candidate i withoutchanging the value of merge_idx (returns to Step S103).

When a block is determined to be available (Step S104, Yes), theintra-inter prediction unit 107 proceeds to the next step.

Next, the intra-inter prediction unit 107 determines whether motion data(a set of mvL0, mvL1, refIdxL0, and refIdxL1, the same applieshereinafter) of the candidate block [i] is a duplicate of motion data(mvL0, refIdxL0, mvL1, and refIdxL1) already tried with previouscandidate blocks [1 . . . (i−1)] (Step S105). This determination will bedescribed later using FIG. 12.

When a block is determined to be a duplicate (Step S105, Yes), theintra-inter prediction unit 107 moves on to the next candidate i withoutchanging the value of merge_idx (returns to Step S103).

When a block is determined to be not a duplicate, that is, when themotion data is a new set of motion data items, (Step S105, No), theintra-inter prediction unit 107 proceeds to the next step. A mergingcandidate list of motion vectors (mergeCandLis) is generated as a resultof the determinations as to the availability (Step S104) and duplication(Step S105). This will be described later using FIG. 11.

Next, the intra-inter prediction unit 107 obtains or derives motion data(mvL0, refIdxL0, mvL1, and refIdxL1) of the candidate block [i] (StepS106). Here, when the candidate block [i] is a co-located block intendedto be used in temporal mode, the scaling process is performed. Thescaling process will be described later using FIG. 14.

Although the scaling process is performed when a candidate block [i]turns out to be a co-located block intended to be used in temporal modein Step S106, the operation of the moving picture coding apparatus isnot limited to this. For example, in another possible operation, motiondata (mvL0, refIdxL0, mvL1, and refIdxL1) already subjected to thescaling process (this will be described later using FIG. 14) is obtainedwhen a co-located block is added to the list of candidate blocks in StepS102, and the co-located block is not added to the list in Step S105when the motion data of the co-located block is a duplicate of motiondata of any of previous candidate blocks (FIG. 17). In this way, moreduplicate motion data of candidate blocks is omitted so that processingload can be reduced and coding efficiency can be improved.

Next, inter coding is performed as a trial by the coding apparatus as awhole using the determined motion data under the control of the codingcontrol unit 108 (Step S107). The coding control unit 108 obtains, forexample, a bitstream [i] as a resultant output from the entropy codingunit 110.

The coding control unit 108 determines whether or not the currentcandidate [i] produces a result better than the results obtained usingprevious candidates [1 . . . (i−1)] (whether or not the currentcandidate [i] yields a maximum value (or a minimum vale) of apredetermined objective function) from viewpoints such as bitstreamlength (compression efficiency) or delay in processing (Step S108).

When it is determined that the current candidate [i] produces a resultbetter than the results produced using the previous candidate [1 . . .(i−1)] (Step S108, Yes), the current value of merge_idx is stored as avalue of merge_idx to be actually used for coding and decoding (StepS109). Briefly, the effective value of merge_idx which yields a morepurposive result is stored in a parameter of dummy_merge_idx.

The intra-inter prediction unit 107 has thus obtained the result thatthe current candidate i is an effective entry. Next, the intra-interprediction unit 107 increments the value of merge_idx to move on to thenext entry (Step S110).

Next, the coding control unit 108 determines whether or not the trialhas been performed on all candidate blocks (Step S111).

When it is determined that the process has been performed on all theblocks (the trial has been performed on the co-located block for the (t)temporal mode set as the last candidate block [N] in Step S102) (StepS111, Yes), the coding control unit 108 proceeds to the next step.

When it is determined that the process has not been performed on all thecandidate blocks (Step S111, No), the candidate number i is incrementedand the trial is performed on the next candidate.

Finally, dummy_merge_idx, which yields a maximum value (or a minimumvale) of a predetermined objective function is determined to be amerging index (merge_idx) to be actually included in a code sequence(Step S112).

This is the operation of coding using the merge mode.

FIG. 10 illustrates merging candidate blocks [1 . . . 6] set in StepS102 by the intra-inter prediction unit 107.

The candidate blocks include (s) one or more spatially neighboringblocks ((s) spatially neighboring blocks [1 . . . (N−1)] in FIG. 10) and(t) one temporally neighboring block ((t) co-located block [N] in FIG.10).

In a merging candidate list, the spatially neighboring blocks are listedas a candidate entry (or candidate entries) having merge_idx of lessvalues, in other words, as a candidate entry (or candidate entries) atthe top of the list. The spatially neighboring blocks are located in adirection (S1) horizontal or (S2) vertical from the current PU andneighbors the current PU there as illustrated in FIG. 10.

It should be noted that the neighborhood is determined on the basis ofPU which is a unit of motion data to which the same motion vector isapplied. In other words, what is determined is whether or not a PUneighbors the CurrentPU which includes the current block Curr_Blk.Blocks B0 to B2 in FIG. 10 are examples of a vertically neighboringblock. A PU including any of the blocks is a neighboring PU, and motiondata (mvL0, refIdxL0, mvL1, and refIdxL1) of the neighboring PU is used.In FIG. 10, blocks A0 and A1 are examples of a horizontally neighboringblock.

The candidate entry having merge_idx of the largest value and located atthe bottom of a merging candidate list, in other words, the candidateentry last added to a merging candidate list is a temporally neighboringblock. In FIG. 10, the co-located block in a picture indicated by anindex value of zero in a reference picture list L1 (or L0 when there isno available reference picture list L1) of a current block is atemporally neighboring block.

FIG. 11 illustrates concept of the merging candidate list(mergeCandList) generated in the process in Steps S103 and later. The“i” (1 . . . 6) on the left of FIG. 11 corresponds to the candidatenumber i in Step S103 and others.

The entries corresponding to i=[1 . . . 5] are (s) one or more spatiallyneighboring blocks (A0 . . . B2 in FIG. 10). The entry corresponding toi=6 is (t) one temporally neighboring block ((t) co-located block [N] inFIG. 10).

An effective one of entry numbers of the candidates 1 . . . 6 ismerge_idx. Referring to FIG. 11, the candidates corresponding to i=3 and5 are duplicate motion vectors. More specifically, this indicates thatthe intra-inter prediction unit 107 has determined in Step S105 thatmotion data (a set of mvL0, mvL1, refIdxL0, and refIdxL1, the sameapplies hereinafter) of the candidate block [i] is a duplicate of motiondata (mvL0, refIdxL0, mvL1, and refIdxL1) already tried with previouscandidate blocks [1 . . . (i−1)]).

FIG. 12 illustrates an example of a duplication determination in Step105 where it is determined that motion data corresponding to an entry ofa candidate block is a duplicate of motion data corresponding to aprevious entry.

When motion data of a neighboring block located at B1 which is directlyabove a current PU is practically determined for a PU which alsoincludes B0 and BN, motion data of the blocks B0 and BN corresponding tothe candidate numbers 3 and 5, respectively, is a duplicate of themotion data of a neighboring block B1 which is directly above a currentPU. Accordingly, the entries of the blocks B0 and BN are removed fromthe list. The list mergeCandList is thereby compressed to a list inwhich the largest value of merge_idx is “2” as illustrated in FIG. 11.

FIG. 13 is a flowchart illustrating a process for obtaining motion data(mvL0, refIdxL0, mvL1, and refIdxL1) of a merging candidate block [i]which is performed in Step S106.

When the process is started, the coding control unit 108 determineswhether a neighboring block [i] is a spatially neighboring block or atemporally neighboring block (Step S201).

When the coding control unit 108 determines that the neighboring block[i] is a spatially neighboring block (the value of [i] is one of 1 to 5in the table in FIG. 11), motion data of the PU including the candidateblock [i] is directly determined to be motion data of a current block(Step S202).

When the coding control unit 108 determines that the neighboring block[i] is a temporally neighboring block (the value of [i] is 6 in thetable in FIG. 11), mvL0Col of the co-locate block (Col_Blk), which isthe candidate block [6], is scaled using a temporal direct scalingprocess including multiplication (Step S203).

This scaling process will be described below using FIG. 14.

FIG. 14 is a flow chart illustrating the scaling process in Step S203.

First, the intra-inter prediction unit 107 calculates DistScaleFactorusing a current picture currPicOrField, a reference picture pic0referenced by a current block, a picture pic 1 including a co-locatedblock, and the value of display order of a reference pic0 referenced bythe co-located block as illustrated by the equation for Step 1 in FIG. 6(Step S301). Next, the intra-inter prediction unit 107 calculates amotion vector mvL0 by multiplying a motion vector mvCol of theco-located block by DistScaleFactor as illustrated by the equation forStep 2 in FIG. 6 (Step S302). Next, the intra-inter prediction unit 107determines whether or not the magnitudes of a horizontal component and avertical component of the calculated motion vector mvL0 can berepresented at a certain bit precision (Step S303). When the result ofthe determination is true (Step S303, Yes), the intra-inter predictionunit 107 adds a merging block candidate having the calculated motionvector mvL0 to a merging candidate list mergeCandlist (Step S304). Whenthe result is false (Step S303, No), the intra-inter prediction unit 107determines that a merging block candidate calculated from a co-locatedblock is not available and does not add the merging block candidate to amerging candidate list mergeCandList (Step S305).

In this way, when a motion vector resulting from the scaling process hastoo large a value to be represented at a certain bit precision, amerging block candidate having the motion vector is not added to amerging candidate list. This makes it possible to limit motion vectorsto be handled in coding and decoding to a magnitude which can berepresented at the certain bit precision. For example, assume that thecertain bit precision is 16 bits. In this case, a merging block having amotion vector mvL0 obtained as a result of the scaling process is notadded to a merging candidate list when either the horizontal componentor the vertical component of the motion vector mvL0 has a value notwithin the range from −32768 to +32767. In this way, it is possible tolimit motion vectors to be handled in coding and decoding to a certainmagnitude such that the motion vectors can be represented at a bitprecision of 16 bits.

The present invention is not limited to above-described example forEmbodiment 1 in which both the horizontal component and the verticalcomponent of a motion vector are limited to a magnitude which can berepresented at a bit precision of 16 bits. For example, assume the casethat the horizontal component is limited to a magnitude which can berepresented at a bit precision of 16 bits and the vertical component islimited to a magnitude which can be represented at a bit precision of 14bits. In this case, a merging block candidate having a motion vectormvL0 obtained as a result of the scaling process is not added to amerging candidate list when it is determined that the horizontalcomponent mvL0 is not within the range from −32768 to +32767 or thevertical component of the motion vector is not within the range from−8192 to 8191. In this way, it is possible to limit the horizontalcomponent of a motion vector to one magnitude and the vertical componentof the motion vector to another magnitude.

The present invention is not limited to the above-described example forEmbodiment 1 in which a motion vector mvL0 of a reference picture listL0 is calculated by the scaling process. The scaling process isapplicable also to calculation of a motion vector mvL1 of a referencepicture list L1.

The present invention is not limited to above-described Embodiment 1 inwhich a merging block candidate calculated from a co-located block isnot added to a merging candidate list when the merging block candidatehas a motion vector mvL0 which is calculated by multiplying a motionvector mvCol of the co-located block by DistScaleFactor in Step S302 andhas a horizontal component and a vertical component either of which hastoo large a value to be represented at a certain bit precision. Forexample, when a co-located block is bi-predictive, a merging blockcandidate may be calculated by performing the process from Steps S302 toS305 using the other motion vector of the co-located block as mvCol. Inthis way, excessive reduction in the number of merging block candidatescalculated from co-located blocks can be avoided, so that codingefficiency can be increased.

The present invention is not limited to above-described Embodiment 1 inwhich a merging block candidate calculated from a co-located block isnot added to a merging candidate list in Step S305 when either thehorizontal component or the vertical component of a motion vector mvL0has too large a value to be represented at a certain bit precision. Forexample, as illustrated in Step S401 in FIG. 15, the horizontalcomponent or the vertical component of the motion vector mvL0 may beclipped so that its value can be represented at a certain bit precision,and a merging block candidate having the clipped motion vector may beadded to a merging candidate list. For a specific example, assume thatthe certain bit precision is 16 bits. In this case, when a motion vectorobtained by the scaling process has a horizontal component having avalue greater than +32767, a merging block candidate can be calculatedusing a motion vector having a horizontal component of +32767 as aresult of clipping. When a motion vector obtained by the scaling processhas a horizontal component having a value less than −32768, a mergingblock candidate can be calculated using a motion vector having ahorizontal component of −32768 as a result of clipping.

The present invention is not limited to above-described example forEmbodiment 1 in which the magnitude of motion vectors is limited to amagnitude based on a fixed bit precision. For example, a flag and a bitprecision for limiting motion vectors may be additionally indicated in aheader such as a sequence parameter set (SPS), a picture parameter set(PPS), and a slice header, and limiting values for motion vectors may bechanged for each sequence, picture, or slice according to the flag andbit precision. Optionally, limiting values for motion vectors may bechanged according to a profile or a level which specifies a bitprecision of a motion vector.

The following will describe a moving picture decoding apparatus whichrestores a moving picture from a bitstream coded by the moving picturecoding apparatus according to Embodiment 1.

FIG. 16 is a block diagram illustrating a configuration of a movingpicture decoding apparatus according to Embodiment 1.

A moving picture decoding apparatus 200 decodes an input coded bitstreamand outputs decoded picture signals buffered in a memory (a memory fordecoded pictures) in display order with predetermined timing.

As illustrated in FIG. 16, the moving picture decoding apparatus 200includes, as its main part, an entropy decoding unit 201, aninverse-quantization unit 202, an inverse-transformation unit 203, anadder unit 204, a memory 207, an intra-inter prediction unit 205, and adecoding control unit 206. Each constituent element having the same nameas that in the moving picture coding apparatus illustrated in FIG. 8 hasa corresponding functionality.

The entropy decoding unit 201 entropy-decodes an input coded bitstreamand outputs a quantized differential signal, a decode control signal,and others.

The inverse-quantization unit 202 inverse-quantizes the quantizeddifferential signal obtained by the entropy decoding. Theinverse-transformation unit 203 inverse-transforms a differential signalobtained by the inverse-quantizing from a frequency domain into an imagedomain and outputs restored differential signal.

The adder unit 204 adds the restored differential signal and apredictive video signal to generate a decoded video signal.

The intra-inter prediction unit 205 stores the decoded video signal onthe basis of a predetermined unit, such as on a per-frame or per-blockbasis, in the memory 207 and, upon instruction from the decoding controlunit 206, generates and outputs a predictive video signal (pixel valuesderived based on the decoded video signal and motion vectors) to beprovided to the adder unit 204.

As with the moving picture coding apparatus 100, the scaling processaccording to Embodiment 1 is performed by the intra-inter predictionunit 205. It should be noted that the intra-inter prediction unit 205 ofthe moving picture decoding apparatus 200 according to Embodiment 1corresponds to an adding unit and a selecting unit, and the entropydecoding unit 201, the inverse-quantization unit 202, theinverse-transformation unit 203, the adder unit 204, etc. collectivelycorrespond to a decoding unit.

The decoding control unit 206 obtains control parameters to use forcontrol of the processing unit in FIG. 16 and decoding of pictures fromthe decoding control signal decoded by the entropy decoding unit 201.The decoding control information in a coded bitstream includes themerging index (merge_idx) determined in Step S112 illustrated in FIG. 9.

FIG. 17 is a flowchart illustrating operation of the moving picturedecoding apparatus according to Embodiment 1.

The following will describe operation to be performed in the case wherethe decoding control unit 206 has determined, from information indicatedby a decode control signal, that a current block (Curr_Blk) (or aprediction unit PU block including the current block) is inter-coded(MODE_INTER) using merge mode (MergeMODE).

First, the intra-inter prediction unit 205 locally generates a mergingcandidate list (mergeCandList) illustrated in FIG. 11. To locallygenerate a merging candidate list means that the intra-inter predictionunit 205 generates a merging candidate list using the same method as themoving picture coding apparatus 100, without referencing informationobtained from a coded bitstream.

The parameter “i=1 . . . 6” has the same definition as “i” in FIG. 11.

The intra-inter prediction unit 205 performs the process from Steps S501to S505 for the candidate block number i which ranges from 1 to 6. Theintra-inter prediction unit 205 identifies the candidate block number i(Step S501). When the candidate block number i is one of 1 to 5, theintra-inter prediction unit 205 obtains motion data of spatialneighboring blocks (Step S502).

When the candidate block number i is 6, the intra-inter prediction unit205 performs the scaling process using motion data of a co-located blockusing the same method as in Step S203 in FIG. 13 (Step S503).

Next, the intra-inter prediction unit 205 determines whether or not themotion data obtained in Step S502 or Step S504 is a duplicate of motiondata in any entry above in mergeCandList (Step S504).

When it is determined that the motion data is a duplicate (Step S504,Yes), the intra-inter prediction unit 205 moves on to the candidateblock number i incremented to the next value.

When it is determined that motion data is not a duplicate (Step S504,No), the intra-inter prediction unit 205 appends the obtained motiondata to the merging candidate list (mergeCandList) (Step S505).

An initial merging candidate list (mergeCandList) is thus generated bythe process from Steps S501 to 5505.

Next, when a predetermined condition is satisfied, the intra-interprediction unit 205 updates the merging candidate list (mergeCandList)(Step S506). FIG. 18 illustrates an example process for the updating,which is performed under a rule implicitly shared with a correspondingmoving picture coding apparatus. (a) in FIG. 18 illustrates an generatedinitial merging candidate list (mergeCandList). (b) in FIG. 18illustrates a merging candidate list after being updated. In the exampleillustrated in (b) in FIG. 18, a candidate having a merging index(merge_idx) of “0” (mvL0_A, ref0) and a candidate having a merging indexof “1” (mvL1_B, ref0) are combined to generate a candidate having amerging index (merge_idx) of “2” (mvL0_A, ref0, mvL1_B, ref0).

In the following, a selection for merge mode is made for motion vectorsmvL0 and mvL1 using the list.

The entropy decoding unit 201 entropy-decodes merge_Idx, and theintra-inter prediction unit 205 receives the value of the merge_Idx(Step S507).

Next, the intra-inter prediction unit 205 selects motion data to use inthe merge mode indicated by the value of the merge_Idx from thecandidates in the merging candidate list (Step S508).

Finally, the intra-inter prediction unit 205 obtains pixel data(pixelsL0 and pixelsL1) of pixels at positions indicated by the motionvectors mvL0 and mvL1 in the selected motion data (mvL0, refIdxL0, mvL1,refIdxL1), and derives a predictive video signal using the pixel data(Step S509).

In this way, when a motion vector resulting from the scaling process hastoo large a value to be represented at a certain bit precision, amerging block candidate having the motion vector is not added to amerging candidate list. This makes it possible to limit motion vectorsto be handled in coding and decoding to a magnitude which can berepresented at the certain bit precision.

The present invention is not limited to above-described Embodiment 1 inwhich after the scaling process in Step S302 in FIG. 14, whether or notthe magnitude of the calculated motion vector can be represented at acertain bit precision is determined. Alternatively, for example, whetheror not the magnitude of the motion vector mvL0 selected according tomerge_idx in Step S508 in FIG. 17 can be represented within a certainlength of bits may be determined. Furthermore, when it is determinedthat the magnitude cannot be represented at a certain bit precision, themotion vector may be clipped so as to have a magnitude which can berepresented at the certain bit precision.

Furthermore, the technique disclosed in Embodiment 1 is applicable notonly to the case where the magnitude of a motion vector after thescaling process using the merge mode specified in the HEVC discussed inNPL 2 is limited so that it can be represented at a certain bitprecision. It is also applicable to the case where a motion vectorpredictor candidate is derived using the AMVP specified in the HEVCdiscussed in NPL 2.

FIG. 19A illustrates a motion vector predictor mvpLX in HEVC describedin NPL 2. FIG. 19B illustrates a candidate list mvpListLX (mvpListL0 andmvpListL1) for the motion vector predictor mvpLX.

The motion vector predictor mvpLX is used for derivation of a differencemotion vector mvdLX which is a difference from a motion vector mvLXderived by motion estimation as illustrated in FIG. 19A. Then, thedifference motion vector mvdLX is coded. The value of mvp_idx_I0 in FIG.19B corresponds to the value of mvp_idx_IX which is coded (or extractedby a corresponding decoding apparatus). Motion data ofmvpListLXN[mvp_idx_IX] identified by an index value (0, 1, or 2) is amotion vector predictor mvp (predictor). N in FIG. 19A and FIG. 19Bindicates a spatial or temporal position of a block whose motion vectorhas a value to be used as a predicted value of a motion vector.

FIG. 20 illustrates predictor candidate blocks or a predictor candidateblock indicated by the value of N (A, B, or Col) shown in FIG. 19B. Thesolid black block in FIG. 20 is a current block to be coded (or decoded)Curr_Blk. The block is included in a picture having a picture number ofpicNum 302. The hatched block in FIG. 20 is located at the positionindicated by approximately identical spatial coordinates (x, y) as thecurrent block to be decoded Curr_Blk (or a prediction unit PU blockincluding the current block) but in a picture having a different picNum(temporally different), that is, what is called a co-located block(Col_Blk). In this example, assume that Col_Blk is located in a picturenot having a picture number of a picNum 302 but having a picture numberof picNum 303. In HEVC, motion vectors mvL0A, mvL0B, and mvL0Col (ormvL1A, mvL1B, and mvL1Col) of the blocks N_Blk (A_Blk, B_Blk, Col_Blk)at the positions A, B, and Col, respectively, are multiplied byDistScaleFactor, and resulting motion vector predictors mvpL0 and mvpL1are used as predictor candidates.

In Embodiment 1, whether or not the magnitude of each of the motionvector predictors calculated by the multiplication can be represented ata certain bit precision is determined. When the result of thedetermination is false, the motion vector predictor is not added to alist of motion vector predictor candidates. In this way, it is possibleto limit a motion vector predictor or a difference motion vectorcalculated from a motion vector and a motion vector predictor of acurrent block to be coded to a magnitude which can be represented at acertain bit precision is determined. When the motion vector predictorcalculated by the multiplication has a magnitude which cannot berepresented at the certain bit precision, a motion vector predictorobtained by clipping the motion vector predictor so as to have amagnitude which can be represented at a certain bit precision may beadded instead to the list of motion vector predictor candidates.

Embodiment 1 has been described by way of example, and the scope of theclaims of the present application is not limited to Embodiment 1. Thoseskilled in the art will readily appreciate that various modificationsmay be made in these exemplary embodiments and that other embodimentsmay be obtained by arbitrarily combining the constituent elements of theembodiments without materially departing from the novel teachings andadvantages of the subject matter recited in the appended Claims.Accordingly, all such modifications and other embodiments are includedin the present disclosure.

Each of the constituent elements in each of the above-describedembodiments may be configured in the form of an exclusive hardwareproduct, or may be realized by executing a software program suitable forthe structural element. The constituent elements may be implemented by aprogram execution unit such as a CPU or a processor which reads andexecutes a software program recorded on a recording medium such as ahard disk or a semiconductor memory. Here, the software program forrealizing the moving picture coding apparatus or the moving picturedecoding apparatus according to Embodiment 1 is a program describedbelow.

Specifically, the program causes a computer to execute a method forcoding pictures on a block-by-block basis, the method including:selectively adding, to a list, a motion vector of each of one or morecorresponding blocks each of which is (i) a block included in a currentpicture to be coded and spatially neighboring a current block to becoded or (ii) a block included in a picture other than the currentpicture and temporally neighboring the current block; selecting a motionvector from among the motion vectors in the list, the selected motionvector being to be used for coding the current block; and coding thecurrent block using the motion vector selected in the selecting, whereinin the adding, a scaling process is performed on a first motion vectorof the temporally neighboring corresponding block to calculate a secondmotion vector, whether the calculated second motion vector has amagnitude that is within a predetermined magnitude range or a magnitudethat is not within the predetermined magnitude is determined, and thesecond motion vector is added to the list as the motion vector of thecorresponding block when it is determined that the second motion vectorhas a magnitude that is within the predetermined magnitude range.

Furthermore, the program causes a computer to execute a method fordecoding pictures on a block-by-block basis, the method including:selectively adding, to a list, a motion vector of each of one or morecorresponding blocks each of which is (i) a block included in a currentpicture to be decoded and spatially neighboring a current block to bedecoded or (ii) a block included in a picture other than the currentpicture and temporally neighboring the current block; selecting a motionvector from among the motion vectors in the list, the selected motionvector being to be used for decoding the current block; and decoding thecurrent block using the motion vector selected in the selecting, whereinin the adding, a scaling process is performed on a first motion vectorof the temporally neighboring corresponding block to calculate a secondmotion vector, whether the calculated second motion vector has amagnitude that is within a predetermined magnitude range or a magnitudethat is not within the predetermined magnitude is determined, and thesecond motion vector is added to the list as the motion vector of thecorresponding block when it is determined that the second motion vectorhas a magnitude that is within the predetermined magnitude range.

Embodiment 2

The processing described in each of embodiments can be simplyimplemented in an independent computer system, by recording, in arecording medium, a program for implementing the configurations of themoving picture coding method (image coding method) and the movingpicture decoding method (image decoding method) described in each ofembodiments. The recording media may be any recording media as long asthe program can be recorded, such as a magnetic disk, an optical disk, amagnetic optical disk, an IC card, and a semiconductor memory.

Hereinafter, the applications to the moving picture coding method (imagecoding method) and the moving picture decoding method (image decodingmethod) described in each of embodiments and systems using thereof willbe described. The system has a feature of having an image coding anddecoding apparatus that includes an image coding apparatus using theimage coding method and an image decoding apparatus using the imagedecoding method. Other configurations in the system can be changed asappropriate depending on the cases.

FIG. 21 illustrates an overall configuration of a content providingsystem ex100 for implementing content distribution services. The areafor providing communication services is divided into cells of desiredsize, and base stations ex106, ex107, ex108, ex109, and ex110 which arefixed wireless stations are placed in each of the cells.

The content providing system ex100 is connected to devices, such as acomputer ex111, a personal digital assistant (PDA) ex112, a cameraex113, a cellular phone ex114 and a game machine ex115, via the Internetex101, an Internet service provider ex102, a telephone network ex104, aswell as the base stations ex106 to ex110, respectively.

However, the configuration of the content providing system ex100 is notlimited to the configuration shown in FIG. 21, and a combination inwhich any of the elements are connected is acceptable. In addition, eachdevice may be directly connected to the telephone network ex104, ratherthan via the base stations ex106 to ex110 which are the fixed wirelessstations. Furthermore, the devices may be interconnected to each othervia a short distance wireless communication and others.

The camera ex113, such as a digital video camera, is capable ofcapturing video. A camera ex116, such as a digital camera, is capable ofcapturing both still images and video. Furthermore, the cellular phoneex114 may be the one that meets any of the standards such as GlobalSystem for Mobile Communications (GSM) (registered trademark), CodeDivision Multiple Access (CDMA), Wideband-Code Division Multiple Access(W-CDMA), Long Term Evolution (LTE), and High Speed Packet Access(HSPA). Alternatively, the cellular phone ex114 may be a PersonalHandyphone System (PHS).

In the content providing system ex100, a streaming server ex103 isconnected to the camera ex113 and others via the telephone network ex104and the base station ex109, which enables distribution of images of alive show and others. In such a distribution, a content (for example,video of a music live show) captured by the user using the camera ex113is coded as described above in each of embodiments (i.e., the camerafunctions as the image coding apparatus according to an aspect of thepresent disclosure), and the coded content is transmitted to thestreaming server ex103. On the other hand, the streaming server ex103carries out stream distribution of the transmitted content data to theclients upon their requests. The clients include the computer ex111, thePDA ex112, the camera ex113, the cellular phone ex114, and the gamemachine ex115 that are capable of decoding the above-mentioned codeddata. Each of the devices that have received the distributed datadecodes and reproduces the coded data (i.e., functions as the imagedecoding apparatus according to an aspect of the present disclosure).

The captured data may be coded by the camera ex113 or the streamingserver ex103 that transmits the data, or the coding processes may beshared between the camera ex113 and the streaming server ex103.Similarly, the distributed data may be decoded by the clients or thestreaming server ex103, or the decoding processes may be shared betweenthe clients and the streaming server ex103. Furthermore, the data of thestill images and video captured by not only the camera ex113 but alsothe camera ex116 may be transmitted to the streaming server ex103through the computer ex111. The coding processes may be performed by thecamera ex116, the computer ex111, or the streaming server ex103, orshared among them.

Furthermore, the coding and decoding processes may be performed by anLSI ex500 generally included in each of the computer ex111 and thedevices. The LSI ex500 may be configured of a single chip or a pluralityof chips. Software for coding and decoding video may be integrated intosome type of a recording medium (such as a CD-ROM, a flexible disk, anda hard disk) that is readable by the computer ex111 and others, and thecoding and decoding processes may be performed using the software.Furthermore, when the cellular phone ex114 is equipped with a camera,the video data obtained by the camera may be transmitted. The video datais data coded by the LSI ex500 included in the cellular phone ex114.

Furthermore, the streaming server ex103 may be composed of servers andcomputers, and may decentralize data and process the decentralized data,record, or distribute data.

As described above, the clients may receive and reproduce the coded datain the content providing system ex100. In other words, the clients canreceive and decode information transmitted by the user, and reproducethe decoded data in real time in the content providing system ex100, sothat the user who does not have any particular right and equipment canimplement personal broadcasting.

Aside from the example of the content providing system ex100, at leastone of the moving picture coding apparatus (image coding apparatus) andthe moving picture decoding apparatus (image decoding apparatus)described in each of embodiments may be implemented in a digitalbroadcasting system ex200 illustrated in FIG. 22. More specifically, abroadcast station ex201 communicates or transmits, via radio waves to abroadcast satellite ex202, multiplexed data obtained by multiplexingaudio data and others onto video data. The video data is data coded bythe moving picture coding method described in each of embodiments (i.e.,data coded by the image coding apparatus according to an aspect of thepresent disclosure). Upon receipt of the multiplexed data, the broadcastsatellite ex202 transmits radio waves for broadcasting. Then, a home-useantenna ex204 with a satellite broadcast reception function receives theradio waves. Next, a device such as a television (receiver) ex300 and aset top box (STB) ex217 decodes the received multiplexed data, andreproduces the decoded data (i.e., functions as the image decodingapparatus according to an aspect of the present disclosure).

Furthermore, a reader/recorder ex218 (i) reads and decodes themultiplexed data recorded on a recording medium ex215, such as a DVD anda BD, or (i) codes video signals in the recording medium ex215, and insome cases, writes data obtained by multiplexing an audio signal on thecoded data. The reader/recorder ex218 can include the moving picturedecoding apparatus or the moving picture coding apparatus as shown ineach of embodiments. In this case, the reproduced video signals aredisplayed on the monitor ex219, and can be reproduced by another deviceor system using the recording medium ex215 on which the multiplexed datais recorded. It is also possible to implement the moving picturedecoding apparatus in the set top box ex217 connected to the cable ex203for a cable television or to the antenna ex204 for satellite and/orterrestrial broadcasting, so as to display the video signals on themonitor ex219 of the television ex300. The moving picture decodingapparatus may be implemented not in the set top box but in thetelevision ex300.

FIG. 23 illustrates the television (receiver) ex300 that uses the movingpicture coding method and the moving picture decoding method describedin each of embodiments. The television ex300 includes: a tuner ex301that obtains or provides multiplexed data obtained by multiplexing audiodata onto video data, through the antenna ex204 or the cable ex203, etc.that receives a broadcast; a modulation/demodulation unit ex302 thatdemodulates the received multiplexed data or modulates data intomultiplexed data to be supplied outside; and amultiplexing/demultiplexing unit ex303 that demultiplexes the modulatedmultiplexed data into video data and audio data, or multiplexes videodata and audio data coded by a signal processing unit ex306 into data.

The television ex300 further includes: a signal processing unit ex306including an audio signal processing unit ex304 and a video signalprocessing unit ex305 that decode audio data and video data and codeaudio data and video data, respectively (which function as the imagecoding apparatus and the image decoding apparatus according to theaspects of the present disclosure); and an output unit ex309 including aspeaker ex307 that provides the decoded audio signal, and a display unitex308 that displays the decoded video signal, such as a display.Furthermore, the television ex300 includes an interface unit ex317including an operation input unit ex312 that receives an input of a useroperation. Furthermore, the television ex300 includes a control unitex310 that controls overall each constituent element of the televisionex300, and a power supply circuit unit ex311 that supplies power to eachof the elements. Other than the operation input unit ex312, theinterface unit ex317 may include: a bridge ex313 that is connected to anexternal device, such as the reader/recorder ex218; a slot unit ex314for enabling attachment of the recording medium ex216, such as an SDcard; a driver ex315 to be connected to an external recording medium,such as a hard disk; and a modem ex316 to be connected to a telephonenetwork. Here, the recording medium ex216 can electrically recordinformation using a non-volatile/volatile semiconductor memory elementfor storage. The constituent elements of the television ex300 areconnected to each other through a synchronous bus.

First, the configuration in which the television ex300 decodesmultiplexed data obtained from outside through the antenna ex204 andothers and reproduces the decoded data will be described. In thetelevision ex300, upon a user operation through a remote controllerex220 and others, the multiplexing/demultiplexing unit ex303demultiplexes the multiplexed data demodulated by themodulation/demodulation unit ex302, under control of the control unitex310 including a CPU. Furthermore, the audio signal processing unitex304 decodes the demultiplexed audio data, and the video signalprocessing unit ex305 decodes the demultiplexed video data, using thedecoding method described in each of embodiments, in the televisionex300. The output unit ex309 provides the decoded video signal and audiosignal outside, respectively. When the output unit ex309 provides thevideo signal and the audio signal, the signals may be temporarily storedin buffers ex318 and ex319, and others so that the signals arereproduced in synchronization with each other. Furthermore, thetelevision ex300 may read multiplexed data not through a broadcast andothers but from the recording media ex215 and ex216, such as a magneticdisk, an optical disk, and a SD card. Next, a configuration in which thetelevision ex300 codes an audio signal and a video signal, and transmitsthe data outside or writes the data on a recording medium will bedescribed. In the television ex300, upon a user operation through theremote controller ex220 and others, the audio signal processing unitex304 codes an audio signal, and the video signal processing unit ex305codes a video signal, under control of the control unit ex310 using thecoding method described in each of embodiments. Themultiplexing/demultiplexing unit ex303 multiplexes the coded videosignal and audio signal, and provides the resulting signal outside. Whenthe multiplexing/demultiplexing unit ex303 multiplexes the video signaland the audio signal, the signals may be temporarily stored in thebuffers ex320 and ex321, and others so that the signals are reproducedin synchronization with each other. Here, the buffers ex318, ex319,ex320, and ex321 may be plural as illustrated, or at least one buffermay be shared in the television ex300. Furthermore, data may be storedin a buffer so that the system overflow and underflow may be avoidedbetween the modulation/demodulation unit ex302 and themultiplexing/demultiplexing unit ex303, for example.

Furthermore, the television ex300 may include a configuration forreceiving an AV input from a microphone or a camera other than theconfiguration for obtaining audio and video data from a broadcast or arecording medium, and may code the obtained data. Although thetelevision ex300 can code, multiplex, and provide outside data in thedescription, it may be capable of only receiving, decoding, andproviding outside data but not the coding, multiplexing, and providingoutside data.

Furthermore, when the reader/recorder ex218 reads or writes multiplexeddata from or on a recording medium, one of the television ex300 and thereader/recorder ex218 may decode or code the multiplexed data, and thetelevision ex300 and the reader/recorder ex218 may share the decoding orcoding.

As an example, FIG. 24 illustrates a configuration of an informationreproducing/recording unit ex400 when data is read or written from or onan optical disk. The information reproducing/recording unit ex400includes constituent elements ex401, ex402, ex403, ex404, ex405, ex406,and ex407 to be described hereinafter. The optical head ex401 irradiatesa laser spot in a recording surface of the recording medium ex215 thatis an optical disk to write information, and detects reflected lightfrom the recording surface of the recording medium ex215 to read theinformation. The modulation recording unit ex402 electrically drives asemiconductor laser included in the optical head ex401, and modulatesthe laser light according to recorded data. The reproductiondemodulating unit ex403 amplifies a reproduction signal obtained byelectrically detecting the reflected light from the recording surfaceusing a photo detector included in the optical head ex401, anddemodulates the reproduction signal by separating a signal componentrecorded on the recording medium ex215 to reproduce the necessaryinformation. The buffer ex404 temporarily holds the information to berecorded on the recording medium ex215 and the information reproducedfrom the recording medium ex215. The disk motor ex405 rotates therecording medium ex215. The servo control unit ex406 moves the opticalhead ex401 to a predetermined information track while controlling therotation drive of the disk motor ex405 so as to follow the laser spot.The system control unit ex407 controls overall the informationreproducing/recording unit ex400. The reading and writing processes canbe implemented by the system control unit ex407 using variousinformation stored in the buffer ex404 and generating and adding newinformation as necessary, and by the modulation recording unit ex402,the reproduction demodulating unit ex403, and the servo control unitex406 that record and reproduce information through the optical headex401 while being operated in a coordinated manner. The system controlunit ex407 includes, for example, a microprocessor, and executesprocessing by causing a computer to execute a program for read andwrite.

Although the optical head ex401 irradiates a laser spot in thedescription, it may perform high-density recording using near fieldlight.

FIG. 25 illustrates the recording medium ex215 that is the optical disk.On the recording surface of the recording medium ex215, guide groovesare spirally formed, and an information track ex230 records, in advance,address information indicating an absolute position on the diskaccording to change in a shape of the guide grooves. The addressinformation includes information for determining positions of recordingblocks ex231 that are a unit for recording data. Reproducing theinformation track ex230 and reading the address information in anapparatus that records and reproduces data can lead to determination ofthe positions of the recording blocks. Furthermore, the recording mediumex215 includes a data recording area ex233, an inner circumference areaex232, and an outer circumference area ex234. The data recording areaex233 is an area for use in recording the user data. The innercircumference area ex232 and the outer circumference area ex234 that areinside and outside of the data recording area ex233, respectively arefor specific use except for recording the user data. The informationreproducing/recording unit 400 reads and writes coded audio, coded videodata, or multiplexed data obtained by multiplexing the coded audio andvideo data, from and on the data recording area ex233 of the recordingmedium ex215.

Although an optical disk having a layer, such as a DVD and a BD isdescribed as an example in the description, the optical disk is notlimited to such, and may be an optical disk having a multilayerstructure and capable of being recorded on a part other than thesurface. Furthermore, the optical disk may have a structure formultidimensional recording/reproduction, such as recording ofinformation using light of colors with different wavelengths in the sameportion of the optical disk and for recording information havingdifferent layers from various angles.

Furthermore, a car ex210 having an antenna ex205 can receive data fromthe satellite ex202 and others, and reproduce video on a display devicesuch as a car navigation system ex211 set in the car ex210, in thedigital broadcasting system ex200. Here, a configuration of the carnavigation system ex211 will be a configuration, for example, includinga GPS receiving unit from the configuration illustrated in FIG. 23. Thesame will be true for the configuration of the computer ex111, thecellular phone ex114, and others.

FIG. 26A illustrates the cellular phone ex114 that uses the movingpicture coding method and the moving picture decoding method describedin embodiments. The cellular phone ex114 includes: an antenna ex350 fortransmitting and receiving radio waves through the base station ex110; acamera unit ex365 capable of capturing moving and still images; and adisplay unit ex358 such as a liquid crystal display for displaying thedata such as decoded video captured by the camera unit ex365 or receivedby the antenna ex350. The cellular phone ex114 further includes: a mainbody unit including an operation key unit ex366; an audio output unitex357 such as a speaker for output of audio; an audio input unit ex356such as a microphone for input of audio; a memory unit ex367 for storingcaptured video or still pictures, recorded audio, coded or decoded dataof the received video, the still pictures, e-mails, or others; and aslot unit ex364 that is an interface unit for a recording medium thatstores data in the same manner as the memory unit ex367.

Next, an example of a configuration of the cellular phone ex114 will bedescribed with reference to FIG. 26B. In the cellular phone ex114, amain control unit ex360 designed to control overall each unit of themain body including the display unit ex358 as well as the operation keyunit ex366 is connected mutually, via a synchronous bus ex370, to apower supply circuit unit ex361, an operation input control unit ex362,a video signal processing unit ex355, a camera interface unit ex363, aliquid crystal display (LCD) control unit ex359, amodulation/demodulation unit ex352, a multiplexing/demultiplexing unitex353, an audio signal processing unit ex354, the slot unit ex364, andthe memory unit ex367.

When a call-end key or a power key is turned ON by a user's operation,the power supply circuit unit ex361 supplies the respective units withpower from a battery pack so as to activate the cell phone ex114.

In the cellular phone ex114, the audio signal processing unit ex354converts the audio signals collected by the audio input unit ex356 invoice conversation mode into digital audio signals under the control ofthe main control unit ex360 including a CPU, ROM, and RAM. Then, themodulation/demodulation unit ex352 performs spread spectrum processingon the digital audio signals, and the transmitting and receiving unitex351 performs digital-to-analog conversion and frequency conversion onthe data, so as to transmit the resulting data via the antenna ex350.Also, in the cellular phone ex114, the transmitting and receiving unitex351 amplifies the data received by the antenna ex350 in voiceconversation mode and performs frequency conversion and theanalog-to-digital conversion on the data. Then, themodulation/demodulation unit ex352 performs inverse spread spectrumprocessing on the data, and the audio signal processing unit ex354converts it into analog audio signals, so as to output them via theaudio output unit ex357.

Furthermore, when an e-mail in data communication mode is transmitted,text data of the e-mail inputted by operating the operation key unitex366 and others of the main body is sent out to the main control unitex360 via the operation input control unit ex362. The main control unitex360 causes the modulation/demodulation unit ex352 to perform spreadspectrum processing on the text data, and the transmitting and receivingunit ex351 performs the digital-to-analog conversion and the frequencyconversion on the resulting data to transmit the data to the basestation ex110 via the antenna ex350. When an e-mail is received,processing that is approximately inverse to the processing fortransmitting an e-mail is performed on the received data, and theresulting data is provided to the display unit ex358.

When video, still images, or video and audio in data communication modeis or are transmitted, the video signal processing unit ex355 compressesand codes video signals supplied from the camera unit ex365 using themoving picture coding method shown in each of embodiments (i.e.,functions as the image coding apparatus according to the aspect of thepresent disclosure), and transmits the coded video data to themultiplexing/demultiplexing unit ex353. In contrast, during when thecamera unit ex365 captures video, still images, and others, the audiosignal processing unit ex354 codes audio signals collected by the audioinput unit ex356, and transmits the coded audio data to themultiplexing/demultiplexing unit ex353.

The multiplexing/demultiplexing unit ex353 multiplexes the coded videodata supplied from the video signal processing unit ex355 and the codedaudio data supplied from the audio signal processing unit ex354, using apredetermined method. Then, the modulation/demodulation unit(modulation/demodulation circuit unit) ex352 performs spread spectrumprocessing on the multiplexed data, and the transmitting and receivingunit ex351 performs digital-to-analog conversion and frequencyconversion on the data so as to transmit the resulting data via theantenna ex350.

When receiving data of a video file which is linked to a Web page andothers in data communication mode or when receiving an e-mail with videoand/or audio attached, in order to decode the multiplexed data receivedvia the antenna ex350, the multiplexing/demultiplexing unit ex353demultiplexes the multiplexed data into a video data bit stream and anaudio data bit stream, and supplies the video signal processing unitex355 with the coded video data and the audio signal processing unitex354 with the coded audio data, through the synchronous bus ex370. Thevideo signal processing unit ex355 decodes the video signal using amoving picture decoding method corresponding to the moving picturecoding method shown in each of embodiments (i.e., functions as the imagedecoding apparatus according to the aspect of the present disclosure),and then the display unit ex358 displays, for instance, the video andstill images included in the video file linked to the Web page via theLCD control unit ex359. Furthermore, the audio signal processing unitex354 decodes the audio signal, and the audio output unit ex357 providesthe audio.

Furthermore, similarly to the television ex300, a terminal such as thecellular phone ex114 probably have 3 types of implementationconfigurations including not only (i) a transmitting and receivingterminal including both a coding apparatus and a decoding apparatus, butalso (ii) a transmitting terminal including only a coding apparatus and(iii) a receiving terminal including only a decoding apparatus. Althoughthe digital broadcasting system ex200 receives and transmits themultiplexed data obtained by multiplexing audio data onto video data inthe description, the multiplexed data may be data obtained bymultiplexing not audio data but character data related to video ontovideo data, and may be not multiplexed data but video data itself.

As such, the moving picture coding method and the moving picturedecoding method in each of embodiments can be used in any of the devicesand systems described. Thus, the advantages described in each ofembodiments can be obtained.

Furthermore, various modifications and revisions can be made in any ofthe embodiments in the present disclosure.

Embodiment 3

Video data can be generated by switching, as necessary, between (i) themoving picture coding method or the moving picture coding apparatusshown in each of embodiments and (ii) a moving picture coding method ora moving picture coding apparatus in conformity with a differentstandard, such as MPEG-2, MPEG-4 AVC, and VC-1.

Here, when a plurality of video data that conforms to the differentstandards is generated and is then decoded, the decoding methods need tobe selected to conform to the different standards. However, since towhich standard each of the plurality of the video data to be decodedconforms cannot be detected, there is a problem that an appropriatedecoding method cannot be selected.

In order to solve the problem, multiplexed data obtained by multiplexingaudio data and others onto video data has a structure includingidentification information indicating to which standard the video dataconforms. The specific structure of the multiplexed data including thevideo data generated in the moving picture coding method and by themoving picture coding apparatus shown in each of embodiments will behereinafter described. The multiplexed data is a digital stream in theMPEG-2 Transport Stream format.

FIG. 27 illustrates a structure of the multiplexed data. As illustratedin FIG. 27, the multiplexed data can be obtained by multiplexing atleast one of a video stream, an audio stream, a presentation graphicsstream (PG), and an interactive graphics stream. The video streamrepresents primary video and secondary video of a movie, the audiostream (IG) represents a primary audio part and a secondary audio partto be mixed with the primary audio part, and the presentation graphicsstream represents subtitles of the movie. Here, the primary video isnormal video to be displayed on a screen, and the secondary video isvideo to be displayed on a smaller window in the primary video.Furthermore, the interactive graphics stream represents an interactivescreen to be generated by arranging the GUI components on a screen. Thevideo stream is coded in the moving picture coding method or by themoving picture coding apparatus shown in each of embodiments, or in amoving picture coding method or by a moving picture coding apparatus inconformity with a conventional standard, such as MPEG-2, MPEG-4 AVC, andVC-1. The audio stream is coded in accordance with a standard, such asDolby-AC-3, Dolby Digital Plus, MLP, DTS, DTS-HD, and linear PCM.

Each stream included in the multiplexed data is identified by PID. Forexample, 0x1011 is allocated to the video stream to be used for video ofa movie, 0x1100 to 0x111F are allocated to the audio streams, 0x1200 to0x121F are allocated to the presentation graphics streams, 0x1400 to0x141F are allocated to the interactive graphics streams, 0x1B00 to0x1B1F are allocated to the video streams to be used for secondary videoof the movie, and 0x1A00 to 0x1A1F are allocated to the audio streams tobe used for the secondary audio to be mixed with the primary audio.

FIG. 28 schematically illustrates how data is multiplexed. First, avideo stream ex235 composed of video frames and an audio stream ex238composed of audio frames are transformed into a stream of PES packetsex236 and a stream of PES packets ex239, and further into TS packetsex237 and TS packets ex240, respectively. Similarly, data of apresentation graphics stream ex241 and data of an interactive graphicsstream ex244 are transformed into a stream of PES packets ex242 and astream of PES packets ex245, and further into TS packets ex243 and TSpackets ex246, respectively. These TS packets are multiplexed into astream to obtain multiplexed data ex247.

FIG. 29 illustrates how a video stream is stored in a stream of PESpackets in more detail. The first bar in FIG. 29 shows a video framestream in a video stream. The second bar shows the stream of PESpackets. As indicated by arrows denoted as yy1, yy2, yy3, and yy4 inFIG. 29, the video stream is divided into pictures as I pictures, Bpictures, and P pictures each of which is a video presentation unit, andthe pictures are stored in a payload of each of the PES packets. Each ofthe PES packets has a PES header, and the PES header stores aPresentation Time-Stamp (PTS) indicating a display time of the picture,and a Decoding Time-Stamp (DTS) indicating a decoding time of thepicture.

FIG. 30 illustrates a format of TS packets to be finally written on themultiplexed data. Each of the TS packets is a 188-byte fixed lengthpacket including a 4-byte TS header having information, such as a PIDfor identifying a stream and a 184-byte TS payload for storing data. ThePES packets are divided, and stored in the TS payloads, respectively.When a BD ROM is used, each of the TS packets is given a 4-byteTP_Extra_Header, thus resulting in 192-byte source packets. The sourcepackets are written on the multiplexed data. The TP_Extra_Header storesinformation such as an Arrival_Time_Stamp (ATS). The ATS shows atransfer start time at which each of the TS packets is to be transferredto a PID filter. The source packets are arranged in the multiplexed dataas shown at the bottom of FIG. 30. The numbers incrementing from thehead of the multiplexed data are called source packet numbers (SPNs).

Each of the TS packets included in the multiplexed data includes notonly streams of audio, video, subtitles and others, but also a ProgramAssociation Table (PAT), a Program Map Table (PMT), and a Program ClockReference (PCR). The PAT shows what a PID in a PMT used in themultiplexed data indicates, and a PID of the PAT itself is registered aszero. The PMT stores PIDs of the streams of video, audio, subtitles andothers included in the multiplexed data, and attribute information ofthe streams corresponding to the PIDs. The PMT also has variousdescriptors relating to the multiplexed data. The descriptors haveinformation such as copy control information showing whether copying ofthe multiplexed data is permitted or not. The PCR stores STC timeinformation corresponding to an ATS showing when the PCR packet istransferred to a decoder, in order to achieve synchronization between anArrival Time Clock (ATC) that is a time axis of ATSs, and an System TimeClock (STC) that is a time axis of PTSs and DTSs.

FIG. 31 illustrates the data structure of the PMT in detail. A PMTheader is disposed at the top of the PMT. The PMT header describes thelength of data included in the PMT and others. A plurality ofdescriptors relating to the multiplexed data is disposed after the PMTheader. Information such as the copy control information is described inthe descriptors. After the descriptors, a plurality of pieces of streaminformation relating to the streams included in the multiplexed data isdisposed. Each piece of stream information includes stream descriptorseach describing information, such as a stream type for identifying acompression codec of a stream, a stream PID, and stream attributeinformation (such as a frame rate or an aspect ratio). The streamdescriptors are equal in number to the number of streams in themultiplexed data.

When the multiplexed data is recorded on a recording medium and others,it is recorded together with multiplexed data information files.

Each of the multiplexed data information files is management informationof the multiplexed data as shown in FIG. 32. The multiplexed datainformation files are in one to one correspondence with the multiplexeddata, and each of the files includes multiplexed data information,stream attribute information, and an entry map.

As illustrated in FIG. 32, the multiplexed data information includes asystem rate, a reproduction start time, and a reproduction end time. Thesystem rate indicates the maximum transfer rate at which a system targetdecoder to be described later transfers the multiplexed data to a PIDfilter. The intervals of the ATSs included in the multiplexed data areset to not higher than a system rate. The reproduction start timeindicates a PTS in a video frame at the head of the multiplexed data. Aninterval of one frame is added to a PTS in a video frame at the end ofthe multiplexed data, and the PTS is set

As shown in FIG. 33, a piece of attribute information is registered inthe stream attribute information, for each PID of each stream includedin the multiplexed data. Each piece of attribute information hasdifferent information depending on whether the corresponding stream is avideo stream, an audio stream, a presentation graphics stream, or aninteractive graphics stream. Each piece of video stream attributeinformation carries information including what kind of compression codecis used for compressing the video stream, and the resolution, aspectratio and frame rate of the pieces of picture data that is included inthe video stream. Each piece of audio stream attribute informationcarries information including what kind of compression codec is used forcompressing the audio stream, how many channels are included in theaudio stream, which language the audio stream supports, and how high thesampling frequency is. The video stream attribute information and theaudio stream attribute information are used for initialization of adecoder before the player plays back the information.

In the present embodiment, the multiplexed data to be used is of astream type included in the PMT. Furthermore, when the multiplexed datais recorded on a recording medium, the video stream attributeinformation included in the multiplexed data information is used. Morespecifically, the moving picture coding method or the moving picturecoding apparatus described in each of embodiments includes a step or aunit for allocating unique information indicating video data generatedby the moving picture coding method or the moving picture codingapparatus in each of embodiments, to the stream type included in the PMTor the video stream attribute information. With the configuration, thevideo data generated by the moving picture coding method or the movingpicture coding apparatus described in each of embodiments can bedistinguished from video data that conforms to another standard.

Furthermore, FIG. 34 illustrates steps of the moving picture decodingmethod according to the present embodiment. In Step exS100, the streamtype included in the PMT or the video stream attribute informationincluded in the multiplexed data information is obtained from themultiplexed data. Next, in Step exS101, it is determined whether or notthe stream type or the video stream attribute information indicates thatthe multiplexed data is generated by the moving picture coding method orthe moving picture coding apparatus in each of embodiments. When it isdetermined that the stream type or the video stream attributeinformation indicates that the multiplexed data is generated by themoving picture coding method or the moving picture coding apparatus ineach of embodiments, in Step exS102, decoding is performed by the movingpicture decoding method in each of embodiments. Furthermore, when thestream type or the video stream attribute information indicatesconformance to the conventional standards, such as MPEG-2, MPEG-4 AVC,and VC-1, in Step exS103, decoding is performed by a moving picturedecoding method in conformity with the conventional standards.

As such, allocating a new unique value to the stream type or the videostream attribute information enables determination whether or not themoving picture decoding method or the moving picture decoding apparatusthat is described in each of embodiments can perform decoding. Even whenmultiplexed data that conforms to a different standard is input, anappropriate decoding method or apparatus can be selected. Thus, itbecomes possible to decode information without any error. Furthermore,the moving picture coding method or apparatus, or the moving picturedecoding method or apparatus in the present embodiment can be used inthe devices and systems described above.

Embodiment 4

Each of the moving picture coding method, the moving picture codingapparatus, the moving picture decoding method, and the moving picturedecoding apparatus in each of embodiments is typically achieved in theform of an integrated circuit or a Large Scale Integrated (LSI) circuit.As an example of the LSI, FIG. 35 illustrates a configuration of the LSIex500 that is made into one chip. The LSI ex500 includes elements ex501,ex502, ex503, ex504, ex505, ex506, ex507, ex508, and ex509 to bedescribed below, and the elements are connected to each other through abus ex510. The power supply circuit unit exS05 is activated by supplyingeach of the elements with power when the power supply circuit unit ex505is turned on.

For example, when coding is performed, the LSI ex500 receives an AVsignal from a microphone ex117, a camera ex113, and others through an AVIO ex509 under control of a control unit ex501 including a CPU ex502, amemory controller ex503, a stream controller ex504, and a drivingfrequency control unit ex512. The received AV signal is temporarilystored in an external memory ex511, such as an SDRAM. Under control ofthe control unit ex501, the stored data is segmented into data portionsaccording to the processing amount and speed to be transmitted to asignal processing unit ex507. Then, the signal processing unit ex507codes an audio signal and/or a video signal. Here, the coding of thevideo signal is the coding described in each of embodiments.Furthermore, the signal processing unit ex507 sometimes multiplexes thecoded audio data and the coded video data, and a stream IO ex506provides the multiplexed data outside. The provided multiplexed data istransmitted to the base station ex107, or written on the recordingmedium ex215. When data sets are multiplexed, the data should betemporarily stored in the buffer ex508 so that the data sets aresynchronized with each other.

Although the memory ex511 is an element outside the LSI ex500, it may beincluded in the LSI ex500. The buffer ex508 is not limited to onebuffer, but may be composed of buffers. Furthermore, the LSI ex500 maybe made into one chip or a plurality of chips.

Furthermore, although the control unit ex501 includes the CPU ex502, thememory controller ex503, the stream controller ex504, the drivingfrequency control unit ex512, the configuration of the control unitex501 is not limited to such. For example, the signal processing unitex507 may further include a CPU. Inclusion of another CPU in the signalprocessing unit ex507 can improve the processing speed. Furthermore, asanother example, the CPU ex502 may serve as or be a part of the signalprocessing unit ex507, and, for example, may include an audio signalprocessing unit. In such a case, the control unit ex501 includes thesignal processing unit ex507 or the CPU ex502 including a part of thesignal processing unit ex507.

The name used here is LSI, but it may also be called IC, system LSI,super LSI, or ultra LSI depending on the degree of integration.

Moreover, ways to achieve integration are not limited to the LSI, and aspecial circuit or a general purpose processor and so forth can alsoachieve the integration. Field Programmable Gate Array (FPGA) that canbe programmed after manufacturing LSIs or a reconfigurable processorthat allows re-configuration of the connection or configuration of anLSI can be used for the same purpose.

In the future, with advancement in semiconductor technology, a brand-newtechnology may replace LSI. The functional blocks can be integratedusing such a technology. The possibility is that the present disclosureis applied to biotechnology.

Embodiment 5

When video data generated in the moving picture coding method or by themoving picture coding apparatus described in each of embodiments isdecoded, compared to when video data that conforms to a conventionalstandard, such as MPEG-2, MPEG-4 AVC, and VC-1 is decoded, theprocessing amount probably increases. Thus, the LSI ex500 needs to beset to a driving frequency higher than that of the CPU ex502 to be usedwhen video data in conformity with the conventional standard is decoded.However, when the driving frequency is set higher, there is a problemthat the power consumption increases.

In order to solve the problem, the moving picture decoding apparatus,such as the television ex300 and the LSI ex500 is configured todetermine to which standard the video data conforms, and switch betweenthe driving frequencies according to the determined standard. FIG. 36illustrates a configuration ex800 in the present embodiment. A drivingfrequency switching unit ex803 sets a driving frequency to a higherdriving frequency when video data is generated by the moving picturecoding method or the moving picture coding apparatus described in eachof embodiments. Then, the driving frequency switching unit ex803instructs a decoding processing unit ex801 that executes the movingpicture decoding method described in each of embodiments to decode thevideo data. When the video data conforms to the conventional standard,the driving frequency switching unit ex803 sets a driving frequency to alower driving frequency than that of the video data generated by themoving picture coding method or the moving picture coding apparatusdescribed in each of embodiments. Then, the driving frequency switchingunit ex803 instructs the decoding processing unit ex802 that conforms tothe conventional standard to decode the video data.

More specifically, the driving frequency switching unit ex803 includesthe CPU ex502 and the driving frequency control unit ex512 in FIG. 35.Here, each of the decoding processing unit ex801 that executes themoving picture decoding method described in each of embodiments and thedecoding processing unit ex802 that conforms to the conventionalstandard corresponds to the signal processing unit ex507 in FIG. 35. TheCPU ex502 determines to which standard the video data conforms. Then,the driving frequency control unit ex512 determines a driving frequencybased on a signal from the CPU ex502. Furthermore, the signal processingunit ex507 decodes the video data based on the signal from the CPUex502. For example, the identification information described inEmbodiment B is probably used for identifying the video data. Theidentification information is not limited to the one described inEmbodiment B but may be any information as long as the informationindicates to which standard the video data conforms. For example, whenwhich standard video data conforms to can be determined based on anexternal signal for determining that the video data is used for atelevision or a disk, etc., the determination may be made based on suchan external signal. Furthermore, the CPU ex502 selects a drivingfrequency based on, for example, a look-up table in which the standardsof the video data are associated with the driving frequencies as shownin FIG. 38. The driving frequency can be selected by storing the look-uptable in the buffer ex508 and in an internal memory of an LSI, and withreference to the look-up table by the CPU ex502.

FIG. 37 illustrates steps for executing a method in the presentembodiment. First, in Step exS200, the signal processing unit ex507obtains identification information from the multiplexed data. Next, inStep exS201, the CPU ex502 determines whether or not the video data isgenerated by the coding method and the coding apparatus described ineach of embodiments, based on the identification information. When thevideo data is generated by the moving picture coding method and themoving picture coding apparatus described in each of embodiments, inStep exS202, the CPU ex502 transmits a signal for setting the drivingfrequency to a higher driving frequency to the driving frequency controlunit ex512. Then, the driving frequency control unit ex512 sets thedriving frequency to the higher driving frequency. On the other hand,when the identification information indicates that the video dataconforms to the conventional standard, such as MPEG-2, MPEG-4 AVC, andVC-1, in Step exS203, the CPU ex502 transmits a signal for setting thedriving frequency to a lower driving frequency to the driving frequencycontrol unit ex512. Then, the driving frequency control unit ex512 setsthe driving frequency to the lower driving frequency than that in thecase where the video data is generated by the moving picture codingmethod and the moving picture coding apparatus described in each ofembodiment.

Furthermore, along with the switching of the driving frequencies, thepower conservation effect can be improved by changing the voltage to beapplied to the LSI ex500 or an apparatus including the LSI ex500. Forexample, when the driving frequency is set lower, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set to a voltage lower than that in the case where the drivingfrequency is set higher.

Furthermore, when the processing amount for decoding is larger, thedriving frequency may be set higher, and when the processing amount fordecoding is smaller, the driving frequency may be set lower as themethod for setting the driving frequency. Thus, the setting method isnot limited to the ones described above. For example, when theprocessing amount for decoding video data in conformity with MPEG-4 AVCis larger than the processing amount for decoding video data generatedby the moving picture coding method and the moving picture codingapparatus described in each of embodiments, the driving frequency isprobably set in reverse order to the setting described above.

Furthermore, the method for setting the driving frequency is not limitedto the method for setting the driving frequency lower. For example, whenthe identification information indicates that the video data isgenerated by the moving picture coding method and the moving picturecoding apparatus described in each of embodiments, the voltage to beapplied to the LSI ex500 or the apparatus including the LSI ex500 isprobably set higher. When the identification information indicates thatthe video data conforms to the conventional standard, such as MPEG-2,MPEG-4 AVC, and VC-1, the voltage to be applied to the LSI ex500 or theapparatus including the LSI ex500 is probably set lower. As anotherexample, when the identification information indicates that the videodata is generated by the moving picture coding method and the movingpicture coding apparatus described in each of embodiments, the drivingof the CPU ex502 does not probably have to be suspended. When theidentification information indicates that the video data conforms to theconventional standard, such as MPEG-2, MPEG-4 AVC, and VC-1, the drivingof the CPU ex502 is probably suspended at a given time because the CPUex502 has extra processing capacity. Even when the identificationinformation indicates that the video data is generated by the movingpicture coding method and the moving picture coding apparatus describedin each of embodiments, in the case where the CPU ex502 has extraprocessing capacity, the driving of the CPU ex502 is probably suspendedat a given time. In such a case, the suspending time is probably setshorter than that in the case where when the identification informationindicates that the video data conforms to the conventional standard,such as MPEG-2, MPEG-4 AVC, and VC-1.

Accordingly, the power conservation effect can be improved by switchingbetween the driving frequencies in accordance with the standard to whichthe video data conforms. Furthermore, when the LSI ex500 or theapparatus including the LSI ex500 is driven using a battery, the batterylife can be extended with the power conservation effect.

Embodiment 6

There are cases where a plurality of video data that conforms todifferent standards, is provided to the devices and systems, such as atelevision and a cellular phone. In order to enable decoding theplurality of video data that conforms to the different standards, thesignal processing unit ex507 of the LSI ex500 needs to conform to thedifferent standards. However, the problems of increase in the scale ofthe circuit of the LSI ex500 and increase in the cost arise with theindividual use of the signal processing units ex507 that conform to therespective standards.

In order to solve the problem, what is conceived is a configuration inwhich the decoding processing unit for implementing the moving picturedecoding method described in each of embodiments and the decodingprocessing unit that conforms to the conventional standard, such asMPEG-2, MPEG-4 AVC, and VC-1 are partly shared. Ex900 in FIG. 39A showsan example of the configuration. For example, the moving picturedecoding method described in each of embodiments and the moving picturedecoding method that conforms to MPEG-4 AVC have, partly in common, thedetails of processing, such as entropy coding, inverse quantization,deblocking filtering, and motion compensated prediction. The details ofprocessing to be shared probably include use of a decoding processingunit ex902 that conforms to MPEG-4 AVC. In contrast, a dedicateddecoding processing unit ex901 is probably used for other processingunique to an aspect of the present disclosure. Since the aspect of thepresent disclosure is characterized by inverse quantization inparticular, for example, the dedicated decoding processing unit ex901 isused for inverse quantization. Otherwise, the decoding processing unitis probably shared for one of the entropy decoding, deblockingfiltering, and motion compensation, or all of the processing. Thedecoding processing unit for implementing the moving picture decodingmethod described in each of embodiments may be shared for the processingto be shared, and a dedicated decoding processing unit may be used forprocessing unique to that of MPEG-4 AVC.

Furthermore, ex1000 in FIG. 39B shows another example in that processingis partly shared. This example uses a configuration including adedicated decoding processing unit ex1001 that supports the processingunique to an aspect of the present disclosure, a dedicated decodingprocessing unit ex1002 that supports the processing unique to anotherconventional standard, and a decoding processing unit ex1003 thatsupports processing to be shared between the moving picture decodingmethod according to the aspect of the present disclosure and theconventional moving picture decoding method. Here, the dedicateddecoding processing units ex1001 and ex1002 are not necessarilyspecialized for the processing according to the aspect of the presentdisclosure and the processing of the conventional standard,respectively, and may be the ones capable of implementing generalprocessing. Furthermore, the configuration of the present embodiment canbe implemented by the LSI ex500.

As such, reducing the scale of the circuit of an LSI and reducing thecost are possible by sharing the decoding processing unit for theprocessing to be shared between the moving picture decoding methodaccording to the aspect of the present disclosure and the moving picturedecoding method in conformity with the conventional standard.

INDUSTRIAL APPLICABILITY

The moving picture coding method and moving picture decoding methodaccording to the present disclosure are applicable to any types ofmultimedia data where the methods are performed with reduced load andthe same coding efficiency using motion vectors having limitedmagnitude. For example, the moving picture coding method and movingpicture decoding method can be useful in data storage, transmission,communication, etc. using mobile phones, DVD apparatuses, and personalcomputers.

What is claimed is:
 1. A decoding method for decoding a current block,the decoding method comprising: deriving a motion vector predictor froma reference block, wherein the reference block is either (i) aneighboring block spatially adjacent to the current block and includedin a current picture, or (ii) a collocated block included in a pictureother than the current picture; adding the derived motion vectorpredictor to a motion vector predictor list (MVP list); and decoding thecurrent block by selecting one of the motion vector predictors from theMVP list, wherein deriving the motion vector predictor includes:calculating a second motion vector by scaling a first motion vector ofthe reference block; determining whether a magnitude of the secondmotion vector is within a predetermined magnitude range; when themagnitude of the second motion vector is within the predeterminedmagnitude range, deriving the motion vector predictor as equal to thesecond motion vector; and when the magnitude of the second motion vectoris not within the predetermined magnitude range, deriving the motionvector predictor by clipping the second motion vector such that themotion vector predictor has a magnitude within the predeterminedmagnitude range, wherein the predetermined magnitude range is based on a16-bit precision of a motion vector.
 2. The decoding method of claim 1wherein the collocated block is included in a picture adjacent to thecurrent picture in a sequence of pictures.
 3. The decoding method ofclaim 1 wherein the collocated block is included in a picture other thana picture adjacent to the current picture in a sequence of pictures. 4.The decoding method of claim 1 wherein the neighboring block spatiallyadjacent to the current block is located above the current block.
 5. Thedecoding method of claim 1 wherein the neighboring block spatiallyadjacent to the current block is located left of the current block. 6.The decoding method of claim 1 wherein the motion vector predictor isassociated with a difference motion vector.
 7. A decoding apparatus fordecoding a current block, the encoding apparatus comprising: memorystoring instructions; and processing circuitry, wherein the processingcircuitry is configured to perform decoding processing based on theinstructions stored in the memory, the decoding processing including:deriving a motion vector predictor from a reference block, wherein thereference block is either (i) a neighboring block spatially adjacent tothe current block and included in a current picture, or (ii) acollocated block included in a picture other than the current picture;adding the derived motion vector predictor to a motion vector predictorlist (MVP list); and decoding the current block by selecting one of themotion vector predictors from the MVP list, wherein deriving the motionvector predictor includes: calculating a second motion vector by scalinga first motion vector of the reference block; determining whether amagnitude of the second motion vector is within a predeterminedmagnitude range; when the magnitude of the second motion vector iswithin the predetermined magnitude range, deriving the motion vectorpredictor as equal to the second motion vector; and when the magnitudeof the second motion vector is not within the predetermined magnituderange, deriving the motion vector predictor by clipping the secondmotion vector such that the motion vector predictor has a magnitudewithin the predetermined magnitude range, wherein the predeterminedmagnitude range is based on a 16-bit precision of a motion vector. 8.The decoding apparatus of claim 7 wherein the collocated block isincluded in a picture adjacent to the current picture in a sequence ofpictures.
 9. The decoding apparatus of claim 7 wherein the collocatedblock is included in a picture other than a picture adjacent to thecurrent picture in a sequence of pictures.
 10. The decoding apparatus ofclaim 7 wherein the neighboring block spatially adjacent to the currentblock is located above the current block.
 11. The decoding apparatus ofclaim 7 wherein the neighboring block spatially adjacent to the currentblock is located left of the current block.
 12. The decoding apparatusof claim 7 wherein the motion vector predictor is associated with adifference motion vector.
 13. A non-transitory computer readablerecording medium storing a program that, when executed on a computingdevice, performs operations comprising: deriving a motion vectorpredictor from a reference block, wherein the reference block is either(i) a neighboring block spatially adjacent to the current block andincluded in a current picture, or (ii) a collocated block included in apicture other than the current picture; adding the derived motion vectorpredictor to a motion vector predictor list (MVP list); and decoding thecurrent block by selecting one of the motion vector predictors from theMVP list, wherein deriving the motion vector predictor includes:calculating a second motion vector by scaling a first motion vector ofthe reference block; determining whether a magnitude of the secondmotion vector is within a predetermined magnitude range; when themagnitude of the second motion vector is within the predeterminedmagnitude range, deriving the motion vector predictor as equal to thesecond motion vector; and when the magnitude of the second motion vectoris not within the predetermined magnitude range, deriving the motionvector predictor by clipping the second motion vector such that themotion vector predictor has a magnitude within the predeterminedmagnitude range, wherein the predetermined magnitude range is based on a16-bit precision of a motion vector.
 14. The non-transitory computerreadable recording medium of claim 13 wherein the collocated block isincluded in a picture adjacent to the current picture in a sequence ofpictures.
 15. The non-transitory computer readable recording medium ofclaim 13 wherein the collocated block is included in a picture otherthan a picture adjacent to the current picture in a sequence ofpictures.
 16. The non-transitory computer readable recording medium ofclaim 13 wherein the neighboring block spatially adjacent to the currentblock is located above the current block.
 17. The non-transitorycomputer readable recording medium of claim 13 wherein the neighboringblock spatially adjacent to the current block is located left of thecurrent block.
 18. The non-transitory computer readable recording mediumof claim 13 wherein the motion vector predictor is associated with adifference motion vector.